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'  REPRINTED    FROM    THK 

Bulletin  of  the  American  Bureau  oe  Geography 

Vol..  II,  September  and  Dkcembbk,  1901 


The  Physiography  of  California 


HAROLD  W.  FAIRBANKS,  Ph.  D. 


WINONA,    MINN. 

JONES  &  KROEGER  PRINTERS 
1901 


Ci  F( 


THE  PHYSIOGRAPHY  OF  CALIFORNIA 

BY    HAROLD    W.    FAIEBANKS,  PH.  D. 

That  portion  of  the  Paeilic  Coast  region  embraced  within  the 
state  of  California  is  characterized  by  a  remarkable  diversity  in  its 
topographic  features.  The  relative  position  of  the  mountain 
ranges,  valleys,  and  plains,  and  the  direction  of  the  prevailing 
winds  have  given  rise  to  great  contrasts  in  climatic  conditions  as 
well  as  a  variety  of  productions.  Regions  of  excessive  heat  con- 
trast with  those  of  perpetual  snow;  regions  of  humidity  with  those 
of  aridity;  while  broad  valleys  devoted  to  fruit  and  grain  adjoin 
mountains  tilled  with  the  precious  metals. 

For  the  full  understanding  of  the  physiography  of  a  region, 
the  student  must  know  something  of  its  geological  history.  How 
especially  true  this  is  of  California  will  appear  in  the  course  of 
this  paper. 

Physiographically,  California  cannot  be  treated  as  a  whole.    It 
is  divided  often  by  sharp  lines    into  strongly  contrasting  provinces 
;^  which  have  been  subjected  to  ditferent  conditions,  and  exhibit  dif- 
I^  ferent  types   and    phases  of   physiographic  development.     In  one 
portion  volcanic  features,  often    but  slightly  modified  by  erosion, 
predominate;  in  another  those  characteristic  of  recently  uplifted 
1  mountain   blocks;    in    another  forms  of  mature  or  far  advanced 
^  topograjjliy;  and  in  still  another  those  resulting  from  coastal  eleva- 
tion or  submergence. 
V  No  other  state  in  the  Union  contains  more  interesting  material' 

<   for   the   study  of   physiography,  and  for  observing  the  l)earing  of 
j  this  upon   human   life,  than   does  California.     Greography  should 
here  attain  a  full  and  symmetrical  development. 

GENERAL  PHYSIOGRAPHIC  FEATURES  OF  THE  PACIFIC  SLOPE 

The  important  features  of  relief  of  the  Pacific  coast  region 
have  a  general  north  and  south  direction  varying  in  places  near  the 
coast  to  northwest  and  southeast.  These  are  a  result  of  structural 
conditions. 


2  THE    PHYSIOGRAPHY    OF    CALIFORNIA 

We  may  distinguish  in  a  broad  way  four  physiographic  divi- 
sions as  we  pass  from  the  Rocky  Mountains  westward  to  the  Pacific 
ocean. 

(1)  The  Great  Basin  and  Plateau  region.  Nevada  and  the 
eastern  portion  of  California  lie  in  the  Great  Basin,  while  eastern 
Oregon  and  Washington  is  occupied  by  a  vast  elevated  tract  con- 
tinuous with  the  Great  Basin  and  known  as  th(- Columbian  plateau. 

(2)  These  areas  are  bordered  upon  the  west  by  an  almost  con- 
tinuous mountain  block  of  great  magnitude,  embracing  many  of 
the  highest  peaks  in  the  United  States.  In  California  where  this 
range  reaches  its  greatest  elevation  it  is  known  as  the  Sierra  Nevada. 
In  northern  California,  Oregon  and  Washington  it  is  termed  the 
Cascade  Range. 

(3)  West  of  this  line  of  mountains  lie  the  most  important 
valleys  of  the  Pacific  Slope.  The  largest  of  these  embraces  the 
San  Joaquin  and  Sacramento  valleys,  known  altogether  as  The 
Great  Valley  of  California.  This  valley  extends  in  a  direction  a 
little  west  of  north  thru  the  heart  of  the  state.  Similarly  situ- 
ated in  Oregon  is  the  Willamette  valley;  and  in  Washington,  the 
large  valley  partly  submerged  by  the  waters  of  Puget  Sound. 

(4)  Separating  this  line  of  valleys  from  the  Pacific  ocean 
there  is  another  series  of  mountains  fully  as  continuous  as  the 
Sierra  Nevada-Cascade  block,  tho  less  elevated,  and  designated  in 
general  terms  as  the  Coast  Ranges. 

Different  ptortions  of  the  Coast  Ranges  are  known  under  dif- 
ferent names.  In  Washington  there  are  the  Olympic  mountains; 
in  northern  California  and  Oregon  the  Klamath  mountains;  and 
thru  California  many  other  local  terms  which  will  be  given  later. 

At  the  southern  end  of  the  Great  Valley  the  Sierra  Nevada 
mountains  blend  with  the  Coast  Ranges  in  a  complex  group.  Con- 
tinuing easterly  beyond  this  point  the  Coast  Range  axis  is  known 
in  a  broad  way  as  the  Sierra  Madre  mountains.  South  of  San 
Bernardino  the  designation  Peninsula  Range  is  applied  to  those 
mountains  which  extend  southerly  into  the  peninsula  of  Lower 
California. 

GEOLOGICAL    HISTORY    AS    RELATED     TO     THE     PRESENT    TOPOGRAPHY 

We  trace  the  beginnings  of  the  broader  features  of  the  present 
topography  far  back  in  Tt^rtiary  time.  Altho  tlic  mountain  axes 
of  the  California    region   were  outlined   at   a  much   more  remote 


THE    PHYSIOGRAPHY    OF    CALIFORNIA  3 

period  yet  those  processes  which  developed  the  penei)l;iin,  the  rem- 
nants of  which  are  to  be  distinguished  uiJon  the  mountain  summits 
over  much  of  the  state,  seem  to  have  carried  on  their  work  thru 
the  middle  and  late  Tertiary. 

The  geography  of  the  state  near  the  close  of  the  Miocene  was 
very  different  from  that  of  the  present  day.  The  ocean  filled  the 
Great  Valley  and  spread  over  large  portions  of  the  Coast  Ranges. 
The  Lassen's  peak  volcanic  ridge  which  now  connects  the  Sierra 
Nevadas  with  the  Cascade  Range  was  not  in  existence  at  that  time 
and  the  Sacramento  valley  was  consecpiently  oj)en  at  the  north.  A 
series  of  more  or  less  connected  hikes  of  fresh  water  stretched  at 
about  ocean  level  across  northeastern  California  into  southern 
Oregon.  Thru  a  protracted  j^eriod  of  erosion,  not  without  inter- 
ruptions, the  Sierra  Nevada  Range  had  been  reduced  to  one  of  low 
relief.  The  streams  flowed  sluggishly  in  broad  valleys,  and  the 
climate  and  vegetation  were  quite  different  from  that  of  the  pres- 
ent day. 

The  Klamath  mountain  region  was  probably  an  island  at  this 
time.  It  had  also  been  worn  down  and  a  peneplain  similar  to  that 
in  the  Sierra  Nevadas  extended  over  much  of  it. 

Remnants  of  an  ancient  peneplain  also  appear  upon  the  moun- 
tains of  southern  California.  They  exhibit  about  the  same  degree 
of  degradation  and  are  to  the  best  of  our  present  knowledge  refer- 
able to  the  same  period  as  those  in  northern  California. 

Toward  the  close  of  the  Miocene  period  important  mountain 
making  movements  affected  the  region  of  the  Coast  ranges.  Pro- 
tracted erosion  followed  the  uplift.  Then  subsidence  took  place 
with  the  deposition  of  extensive  beds  whose  position  is  on  the  bor- 
der land  between  the  Miocene  and  Pliocene.  After  the  deposition 
of  these  beds  uplift  and  folding  again  occurred.  Then  the  Coast 
ranges  app(nAr  to  have  been  submerged  again  with  the  deposition 
of  beds,  both  fresh  water  and  marine  of  Pliocene  age. 

The  movements  of  the  central  Coast  ranges  were  undoubtedly 
felt  in  the  Klamath  mountains  and  in  the  Sierra  Nevadas,  but  we 
have  not  there  the  criteria  to  distinguish  them  as  certainly.  There 
were  intervals  of  renewed  canon  cutting  in  these  latter  regions  but 
the  sum  total  of  the  results  seems  to  have  been  a  continuation  of 
the  base  leveling. 

A  large  part  of  the  Pliocene  was  probably  a  period  of  depres- 
sion in  the  whole   Pacific   coast  region.      The  Coast   ranges   were 


4  THE    PHYSIOGRAPHY   OF    CALIFORNIA 

however  not  as  completely  submerged  as  in  the  Miocene,  and  there 
are  reasons  for  believing  that  the  oldest  recognizable  peneplain  rem- 
nants date  from  this  time. 

Extending  south  from  the  Klamath  mountains  nearly  to  San 
Francisco  bay  there  is  an  ancient  plain  truncating  the  mountains. 
During  the  Pliocene  it  received  the  finishing  touches  as  did  also 
that  upon  the  Sierra  Nevadas  and  in  Southern  California. 

The  north  and  south  mountain  lilocks  of  the  Great  Basin  region 
may  have  originated  during  Cretaceous  time;  but  toward  the  close 
of  the  Tertiary  renewed  movements  affected  them.  The  Sierra 
Nevadas  were  raised  Isy  a  tilting  of  the  block  until  it  reached  a 
hight  perhaps  as  great  as  the  present.  Similar  fault  movements 
must  also  have  disturbed  the  Coast  ranges,  in  places  breaking  up 
the  Pliocene  peneplain.  Volcanic  outbreaks  were  associated  with 
the  movements  of  late  Tertiary  time.  At  the  northern  end  of  the 
Sierra  Nevadas  the  outpouring  lava  filled  up  the  depressed  basin 
and  formed  the  Lassen's  peak  volcanic  ridge.  Farther  north  they 
built  up  the  great  Cascade  platform. 

Volcanic  action  at  several  distinct  periods  filled  up  the  ancient 
river  channels  of  the  northern  Sierra  Nevadas  forcing  the  streams 
to  seek  new  ones.  Volcanic  action  also  occurred  in  portions  of  the 
Coast  ranges  upon  an  extensive  scale  and  upon  the  coast  islands. 
Thus  we  find  that  near  the  close  of  the  Tertiary  period  the  geographic 
features  of  the  Pacific  slo^je  underwent  a  radical  transformation. 

Erosion  actively  took  up  the  task  of  destroying  the  newly  ele- 
vated mountain  blocks.  In  the  Sierra  Nevadas.  Klamath  mountains, 
and  in  the  Sierra  Madre  of  southern  California  the  great  canons  of 
the  present  day  were  begun.  Erosion  went  on  actively  also  in  the 
Coast  ranges  and  the  details  of  the  present  drainage  were  worked 
out,  but  here  the  larger  valleys  of  the  present  day  were  already  in 
existence.  They  originated  in  part  during  the  folding  at  the  close 
of  the  Pliocene,  and  in  part  earlier  as  a  result  of  the  combined 
influence  of  structure  and  erosion.  The  whole  region  under  dis- 
cussion must  have  attained  an  elevation  greater  than  the  present 
and  maintained  this  elevation  until  the  canons  had  attained  nearly 
their  present  proportions. 

Concomitant  with  this  elevation,  and  perhaps  as  a  result  of  it, 
the  Sierra  Nevadas.  Klamath  mountains  and  Cascade  range  became 
glaciated.  The  scouring  of  the  ice  modified  the  mountain  topog- 
raphy somewhat,  especially  the  canons,  leaving  as  a  heritage  to  the 


THE    PHYSKHHiAPHY    OF    (•ALIF(JRNIA  O 

present  day  the  hundreds  of  basins  in  which  lie  the  heautiful  hikes 
so  thickly  scattered  thru  the  hit;h  Sierras. 

The  Glacial  period  was  followed  l)y  a  treneral  depression  until 
the  Coast  ran<ies  were  submeriijed  1,000  to  l.oOOfeet  below  the  level 
now  existintJ^.  During  the  period  of  submergence  partial  peneplains 
were  formed  in  different  portions  of  tlie  Coast  ranges  where  the 
conditions  W(^re  favorable.  As  the  country  began  to  rise  the  ter- 
races wdiich  are  so  characteristic  of  the  ocean  front  and  of  many  of 
the  river  valleys  came  into  existence.  The  movement  continued 
until  the  coast  was  again  several  hundred  feet  higher  than  now. 
Finally  came  the  last  submergence  drowning  the  mouths  of  the 
streams  and  giving  rise  to  San  Francisco  bay. 

These  are,  as  far  as  they  are  known,  the  chief  events  which 
have  left  their  impress  upon  the  topography.  From  this  brief  out- 
line it  is  not  difficult  to  see  that  the  topographic  features  of  Cali- 
fornia are  the  result  of  many  and  diverse  physical  conditions.  At 
the  present  time  a  discussion  of  the  topography  in  all  its  phases 
can  only  be  tentative.  Much  more  investigation  is  necessary  before 
we  can  be  sure  that  we  have  a  true  story  of  even  the  recent  geolog- 
ical events  upon  the  Pacific  coast. 

TOPOGRAPHIC    PROVINCES 

For  convenience  of  discussion  the  state  will  l)e  divided  into  the 
following  provinces:  (1)  The  Sierra  Nevada  mountains,  (2)  The 
Great  Basin  region,  (3)  The  Volcanic  Plateau  region,  (4)  The 
Great  Valley  of  California.  (5)  The  Coast  ranges,  (6)  The  Klamath 
mountains.  (7)  The  Sierra  Madre  and  Peninsula  ranges,  (8) 
Coastal  features. 

Some  of  the  divisions  here  made  are  natural  ones,  others  are 
assumed  for  convenience.  For  instance,  the  Klamath  mountains. 
Coast  ranges  and  Sierra  Madre  mountains  constitute  a  continuous 
mountain  axis  the  whole  length  of  the  state.  The  drainage  features 
also  are  not  defined  by  the  boundaries  of  the  different  provinc(^s. 
The  Pitt  river  rises  in  the  volcanic  plateau  region  and  crossing  the 
axis  of  the  Sierra  Nevada -Cascade  block  joins  the  Sacramento  in 
the  Great  Valley. 

The  Sierra  Nevada  Mountains.  The  Sierra  Nevada  mountains 
extend  from  about  thirty-five  degrees  north  latitude  in  a  northerly 
direction,  and  finally  a  little  northwesterly  nearly  to  Lassen"s  peak 
in  latitude  forty  degrees,  thirty  minutes;  thus  having  a  length  of 


t)  THE    PHYSIOGRAPHY    OF    CALIFORNIA 

about  four  Imiulred  miles  and  a  width  aA-eraijing  nearly  eighty  miles. 
The  highest  i)orti()n  of  the  range,  and  that  which  forms  its  water- 
shed, lies  very  close  to  its  eastern  edge.  For  fully  two  hundred 
miles  thru  the  central  portion  of  the  range  this  divide  is  seldom 
lower  than  11,000  feet  and  scores  of  peaks  attain  an  elevation  of 
nearly  14,000  feet,  Mount  Whitney  reaching  14,522  feet. 

The  range  rises  very  slowly  from  the  Great  Valley  upon  the 
west  but  breaks  otf  with  exceeding  ruggedness  upon  the  east. 
Except  toward  its  northern  end  this  mountain  range  is  practically 
a  unit  so  far  as  its  history  is  concerned.  The  elevation  to  the  i^res- 
ent  great  liight  has  l)een  brought  about  thru  the  formation  of  a  fis- 
sure or  series  of  fissures  at  its  eastern  base.  Upon  their  western 
side  the  mountain  ridges  descend  practically  to  sea  level,  but  owing 
to  the  long  gentle  slope  the  elevation  of  the  range  cannot  be  appre- 
ciated from  that  side.  It  is  only  wdien  seen  from  the  valleys  at  the 
base  of  the  fault  scarp  that  the  magnitude  of  the  range  can  be 
appreciated.  Altlio  these  valleys  vary  from  2,500  to  6,000  feet  in 
altitude,  yet  the  wall  of  rock  forming  the  scarp  rises  so  abruptly 
and  with  such  colossal  proportions  that  it  is  almost  overpowering 
in  its  grandeur. 

Upon  the  south  the  range  has  often  been  considered  as  termi- 
nating at  Tehachapai  'i^ass  with  an  elevation  of  8800  feet,  the 
mountains  continuing  to  the  west  of  the  i^ass  and  connecting  with 
the  Coast  ranges,  being  known  as  the  Tehachapai  range.  The  dis- 
tinction thus  made  is  immaterial  to  the  main  fact  that  topographic- 
ally the  Sierra  Nevada  mountains  bend  around  the  southern  end  of 
the  Great  Valley  and  connect  with  the  Coast  ranges. 

The  mighty  eastern  fault  scarp  in  all  its  distinctness  may  be 
considered  as  beginning  in  the  vicinity  of  Walker's  pass,  a  low  por- 
tion of  the  divide  east  of  Kern  Valley.  With  a  gentle  curve  the 
mountain  wall  sweeps  toward  the  north  rising  higher  and  higher 
for  one  hundred  miles  until  culnnnating  northwest  of  Owen's  lake 
in  jagged  peaks  of  the  Mount  Whitney  region.  From  this  point 
for  another  one  hundred  miles  northerly  there  is  but  a  slight  low- 
ering of  the  crest  of  the  range,  altho  the  displacement  by  faulting 
which  at  the  lower  end  of  Owen's  valley  is  as  much  as  10,000  feet, 
decreases  to  not  more  than  5,000  or  (5,000  feet  in  the  Mono  lake 
basin. 

As  we  approach  Lake  Tahoe  the  single  fault  zone  is  replaced 
by  two.  the  ruggedness  of  the  range  gradually  decreasing  as  Mt. 


THE    PHYSIOGRAPHY    OF    CALIFORNIA  7 

Lassen  is  a^jproached.  Lake  Tahoe  lies  in  a  depression  due  to  the 
formation  of  two  fault  scarps  and  the  dropping  of  the  eastern  block. 
South  of  Honey  Lake  valley  the  scarp  of  the  eastern  l)lock  presents 
a  bold  front  to  the  northeast  fully  -iSM)  feet  hi<ih. 

As  we  approach  Mt.  Lassen  the  older  crystalline  rocks  of  the 
Sierra  Nevada  mountains  disappear  under  the  comparatively 
modern  lavas  of  the  volcanic  plateau  of  northeastern  California. 

Viewed  from  the  summit  of  the  Inyo  range  lying  to  the  east  of 
the  highest  portion  of  the  Sierra  Nevada  fault  scarp  the  evenness 
of  the  crest  of  the  latter  is  most  remarkable.  The  great  peaks 
like  Whitney  are  not  isolated  as  are  those  of  the  Cascade  range  but 
lose  their  individuality  in  the  mass  etfect.  This  uniform  sky  line 
which  appears  as  we  view  the  mountains  from  a  distance,  becomes, 
as  we  investigate  them  more  closely,  but  a  cover  for  a  complexity 
of  canons  and  gorges  of  great  depth  and  jjicturesqueness. 

If  we  discard  the  deep  canons,  the  peneplain  character,  of  tlie 
crest  of  the  Sierra  Nevadas.  appears  most  strikingly  from  almost 
any  point  giving  a  good  view  over  extensive  areas.  Many  of  the 
highest  peaks  including  Mount  Whitney  have  flat  or  gently  sloping 
summits  bordered  by  precipitous  walls.  As  one  ascends  the  long 
gently  inclined  ridges  of  the  western  slope  he  is  constantly  reminded 
of  an  ancient  plain  now  elevated  and  undergoing  degradation.  The 
evenness  of  this  plain  is  often  enhanced  by  the  comparatively  uni- 
form surface  of  the  old  river  beds  which  cap  the  ridges  between 
many  of  the  canons  of  the  central  and  northern  Sierras. 

The  streams  of  the  old  peneplain  before  the  re-elevation  of  the 
mountains,  were  choked  with  waste  and  mingled  in  this  waste  was 
the  gold  from  the  broken  down  quartz  veins.  Toward  their  head- 
waters the  topography  was  undoubtedly  quite  rugged  in  places,  but 
by  far  the  greater  portion  of  the  western  slope,  thru  continued 
erosion  and  the  choking  of  the  streams,  was  destitute  of  any  marked 
relief.  The  older  gravels  date  from  the  Miocene  or  earlier  times 
and  the  discordance  ])etween  these  and  the  more  recent  ones  indi- 
cated periods  of  disturbance. 

The  volcanic  outbreaks  inaugurated  in  late  Pliocene  were  con- 
tinued thru  a  considerable  interval  of  time.  The  lavas  flowed  from 
fissures  along  the  crest  of  the  range  near  lines  of  disturbance. 
They  increased  in  amount  toward  the  northern  portion  of  the  range 
where  the  eruptions  of  mud.  ashes,  and  lava  flowing  down  the  val- 
leys completely  buried  them.     The  most  remarkable  flow  remaining 


8  THE    PHYSIOGRAPHY    OF    CALIFORNIA 

is  that  known  as  Tal)l(Mnountain.  This  is  found  in  Tuolumne 
county  and  extends  from  the  high  mountains  many  miles  down  into 
the  foothills.  The  country  about  it  is  now  lower  and  many  tunnels 
have  been  run  under  it  to  obtain  the  Q;old  in  the  buried  gravels. 

The  volcanic  material  deposited  in  the  river  beds  whether  frag- 
mental  or  massive  appears  to  have  been  quite  resistant  to  erosion 
and  so  in  many  cases  pc^nnanently  displaced  the  old  streams.  In 
the  southern  portion  of  the  Sierras  there  was  little  or  no  volcanic 
capf)ing  and  the  old  channels  have  been  practically  removed  since 
the  uplift  of  the  mountains.  It  is  prol^able  also  that  thru  the  cen- 
tral Sierras  the  uplift  was  greater  than  farther  north,  so  that 
erosion  would  be  more*  vigorous. 

In  the  region  of  the  high  Sierras  rise  those  streams  whose 
canons  have  made  the  scenery  of  these  mountains  famous.  The 
Tuolumne,  Merced,  San  Joaquin,  Kings,  and  Kern  rivers  have 
eroded  canons  3,000-5,000  feet  deep.  The  most  noted  of  these  are 
the  Yosemite  valley,  Hetch-Hetchy  valley,  and  Kings  river  canon. 

The  most  of  the  streams  which  have  cut  the  great  canons  have 
not  yet  reached  a  graded  condition  unless  it  be  near  the  borders  of 
the  mountains  where  they  emerge  upon  the  [)lains  of  the  Great 
Valley.  Their  banks  are  generally  steep  and  but  little  bottomland 
exists  along  them.  Near  the  southern  end  of  the  Sierras,  however, 
as  well  as  at  the  north,  there  are  valleys  of  considerable  extent 
seemingly  pointing  towards  a  longer  existence  of  the  present  con- 
ditions in  those  regions  coupled  with  a  lesser  amount  of  uplift.  At 
the  south  the  Kern  valley  is  a  notable  example,  while  the  Sierra 
valley  at  the  north  is  even  larger  in  extent. 

The  drainage  of  th(»  eastern  slope  of  the  Sierra  Nevada  moun- 
tains is  short,  but  the  streams  descend  with  great  velocity  to  the 
valleys  of  the  interior  basin.  The  larger  ones  are  Owens,  Walker, 
Carson,  and  Truckee  rivci's. 

The  formation  of  a  double  fault  block  from  a  point  a  little 
south  of  Lake  Tahoe  has  given  rise  to  the  Tahoe-Sierra  valley  thru 
a  partial  dropping  of  the  eastern  l)lock.  The  eastern  face  of  the 
latter  block  gives  rise  to  the  bold  niouri tains  southwest  of  Honey 
Lake  valley.  In  the  Ta,ho(^-Sierra  valley,  close  under  the  fault 
scarp  of  tlie  western  l)lock.  lie  Lakes  Tahoe,  Donner,  Independence 
and  Wel)er.  These  nve  all  drained  by  the  Truckee  river  which 
flows  easterly  and  northerly  across  the  dro^jped  block,  reaching 
finally  to  pyramid  lake  in  the  Great  Basin. 


THE    PHYSIOGRAPHY    OF    rAI,IF<  )KNIA 


TH  1:    Vi  iS1-;M  1  I  1.     1    A  1.  l.>. 

LakcTalior  is  the  larL^est  of  the  bodiesof  ^vat('l•  aloii<j,-  \\\v  l)as<> 
of  the  fault  sc-arp.  It  is  one  of  the  most  beautiful  lakes  alsoof  the 
whole  Sierras.  It  o%ves  its  existence  to  a  lava  dam  formed  across 
the  ancient  valley  of  the  upper  Truckee  river.  This  fault  scarp 
extends  north  of  the  lakes  l)oundinii-  Sicn-ra  and  jNIohawk  valleys 
iipon   the   west,  but    t;radually    disappears.     This    has    permitted 


10  THE    PHYSIOGRAPHY    OF    CALIFORNIA 

FeathtT  river  to  extend  its  Lasiii  eastward  so  as  to  drain  both  the 
valleys  mentioned  westward  into  the  Sacramento. 

Waterfalls  of  threat  hit^ht  and  l)eaiity  are  frequently  found 
where  the  smaller  streams  join  the  main  rivers,  as  in  the  case  of 
those  in  the  Yosemite  valley.  The  fairly  uniform  hardness  of  the 
rocks,  chiefly  granitic  over  large  areas,  has  resulted  more  often  in 
swift  rapids  than  in  waterfalls. 

The  gold  bearing  belt  upon  the  western  slope  of  the  Sierra 
Nevada  mountains  is  known  world-wide.  The  Mother  Lode,  a 
series  of  gold  bearing  (juartz  veins  extending  for  more  than  100 
miles  thru  the  foothills,  exhibits  in  i^laces  such  large  bodies  of 
quartz  as  to  have  had  considerable  effect  upon  the  topography.  The 
system  of  fault  plains  running  parallel  to  the  range  thru  the 
mineral  region  has,  in  connection  with  dikes  of  igneous  and  meta- 
morphic  rocks  of  varying  hardness,  determined  in  great  measure 
the  courses  of  the  smaller  streams  in  the  western  or  foothill  l)elt. 
They  exhibit  a  fairly  complete  adjustment  to  such  conditions,  but 
the  main  courses  of  all  the  larger  streams  are  consequent  upon  the 
slope  of  the  mountains. 

From  the  relation  of  the  glaciated  surfaces  to  the  present 
canons  it  is  believed  that  the  latter  were  largely  excavated  before 
the  Glacial  i^eriod.  It  is  probable  that  the  ice  during  this  time 
nowhere  reached  much  below  1,000  feet  in  the  Sierras,  while  toward 
their  southern  end  8,000  feet  was  the  limit. 

Th(^  higher  portions  of  the  mountains  were  swept  bare  of  all 
loose  and  disintegrated  material  by  the  ice,  and  the  harder  rocks, 
generally  granitic,  were  finely  grooved  and  polished.  Glacial 
moraines  are  particularly  well  shown  upon  the  eastern  slope  where 
the  ice  streams  passed  out  of  the  canons  on  to  the  edge  of  the  des- 
ert basins.  Vast  quantities  of  fragmental  material  thus  encumber 
the  mouths  of  many  canons  and  in  some  cases  have  given  rise  to 
beautiful  lakes.  The  basins  at  the  heads  of  the  streams  often 
exhibit  very  finely  the  characters  of  glacial  cirques,  being  walled 
in  upon  their  upper  sides  by  nearly  precipitous  cliffs  1.000-2,000 
feet  high.  The  canons  descend  by  successive  steps  from  these 
cirques  at  their  head  to  a  point  near  the  foot  of  the  fault  scarp. 
Many  of  the  basins  are  occupied  by  lakes  wdiich  are  either  entirely 
rock  rimmed  or  inclosed  upon  their  lower  edges  by  morainal  walls. 

The  rolling,  rock-ribbed  surface  of  the  high  Sierras  is  fairly 
(lotted  with  glacial  lakes.    These  elevated  regions  with  their  bare  and 


THE    PHYSIOGRAPHY    OF    CAMFoKMA 


11 


polish(j(l  rocks  appear  to  have  beou  f,'laciate(l  so  recently  that  it 
lias  been  thought  that  the  Glacial  period  was  later  here  than  in  the 
eastern  portion  of  the  continent. 

Various  exphinations  have  been  <:;iven  to  account  for  the 
remarkable  features  of  the  Yosemite  valley.  This  valley  lies  in 
the  heart  of  the  Sierras  and  is  traversed  l)y  the  Merced  river  which 


EL  CAl'ilAN,   VUSEMiii,. 


enters  it  by  a  series  of  rapids  and  waterfalls,  and  leaves  by  a  nar- 
row canon.  The  valley  floor,  which  is  about  three-fourths  of  a  mile 
wide  and  ei^ht  miles  lonu.  has  an  elevation  of  4.000  feet,  while  the 
mountains  enclosing  it  rise  3,000-5,000  feet  more.  Some  portions 
of  the  inclosint;  wall  are  practically  vertical  to  hights  varying  from 
3.000-4,000  f(H^t.  The  Yosemite  creek  enters  the  valley  in  three 
falls  measuring  altogether  2,700  feet. 


12  THE    PHYSIOGRAPHY   OF    CALIFORNIA 

A  study  of  the  structure  of  the  cjranitic  rock  of  the  region 
shows  that  it  is  traversed  l)y  systems  of  joint-planes.  Where  these 
are  inclined  the  walls  are  slopint?,  but  where  the  main  system  is 
vertical  the  atjentsof  erosion,  water  and  ice.  have  widened  the  canon 
to  a  valley  with  steep  or  vertical  walls.  It  is  also  probable  that 
where  the  valley  lies  the  rocks  were  exceptionally  fissured  and  thus 
more  readily  disinte<i;rated  and  eroded.  This  joint  structure  in  the 
.granite  has  controlled  much  of  the  detail  in  the  scenery  of  the  whole 
Sierra  Nevada  range. 

Portions  of  the  granite  of  the  high  Sierras,  especially  in  the 
vicinity  of  the  Yosemite  and  Kings  river  canon,  weathers  out  in 
great  dome-like  forms.  This  is  undoubtedly  produced  thru  concen- 
tric weathering  in  portions  of  the  rock  not  so  permeated  with  joint 
planes.  The  great  south  dome  of  the  Yosemite  is  a  typical  example. 

The  same  agents  then  which  have  produced  the  great  canons 
have  given  rise  to  the  Yosemite,  only  here  they  have  been  aided  by 
exceptional  conditions  in  the  rocks. 

The  Great  Basin  Region.  In  the  early  Cretaceous  the  Sierra 
Nevada  and  Great  Basin  ranges  were  not  in  existence.  It  is 
believed  however  that  the  region  as  a  whole  was  consideral^ly  ele- 
vated l)ut  owing  to  earth  strains  was  at  last  brought  into  a  condition 
of  unstable  ecpiilibrium.  This  resulted  in  the  formation  of  north 
and  south  fissures  and  the  whole  region  between  the  present 
Sierras  and  the  Wasatch  range  broke  up  into  a  series  of  crust 
blocks.  Tli(^  crust  blocks  moved  upon  each  other,  some  sinking, 
others  rising.  The  depressed  one  gave  rise  to  the  valleys,  the 
uplifted  ones  to  the  mountain  ranges.  Movements  along  these 
fault  fissures  have  continued  at  times  to  be  manifested  down  even 
to  the  recent  period.  As  late  as  1872  displacements  as  great  as 
forty  feet  took  place  in  Owen's  valley  and  at  other  points  thru 
western  Nevada. 

The  disturbances  which  elevated  the  Sierra  Nevada  mountains 
at  or  near  the  close  of  the  Pliocene  probably  also  affected  many 
other  ranges  of  the  Great  Basin,  for  the  fault  scarps  of  many  of 
them  are  fully  as  abrupt  as  that  of  the  eastern  face  of  the  Sierras. 

The  valleys  of  the  Great  Basin  are  generally  hot  and  arid. 
They  range  in  elevation  from  that  of  Death  valley,  about  sixty-nine 
feet  below  sea  level  to  6,000  feet  above.  The  mountain  ranges  are 
high,  many  of  them  reaching  an  elevation  of  10,000  feet.  The  Inyo 
and  Wliitc  mountain  ranges  attain   an  elevation  in   places  nearly 


THE    PHYSIOGRAPHY    OF    CALIFORNIA  18 

equal  to  that  ot"  the  Sierra  Nevada,  White  moimtaiu  peak  at  the 
extreme  northern  end  of  the  latter  ran}i;e  towering  to  1-4,000  feet. 

That  portion  of  the  Great  Basin  within  California  exhibits  two 
distinct  phases  of  topographic  development.  (1 )  That  lyin^  east 
of  the  Sierra  Nevada.  This  is  typical  of  the  Great  Basin  as  a 
whole;  that  is,  it  is  characterized  by  arid  or  semi-arid  valleys 
inclosed  between  hi^^h  and  rugged  north  and  south  mountain  ranges. 
(2)  That  in  southeastern  California  lying  between  the  Sierra 
Nevada  and  Sierra  Madre  ranges,  and  including  the  Colorado  desert. 
The  northern  part  is  an  elevated  region  known  in  general  terms  as 
the  Mojave  desert.  It  is  characterized  by  a  lack  of  recently  faulted 
crustal  blocks  and  has  an  irregular  mountain  structure.  The 
mountains  are  low  and  nearly  buried  in  their  own  waste,  which 
has  accumulated  for  a  long  time  in  the  inclosed  basins.  This  latter 
region  is  typical  of  an  old  topography  and  may  with  reason  be  con- 
sidered as  an  illustration  of  how  the  Great  Basin  would  a])])ear  as 
a  whole  if  it  had  not  been  broken  up  by  faulting. 

In  discussing  the  features  of  the  Great  Basin  in  detail,  the 
portion  exhibiting  low  relief  will  be  taken  up  first.  The  basin  of 
the  Colorado  desert  is  separated  from  the  Mojave  desert  by  a  low 
range  of  mountains  forming  the  southeastern  continuation  of  the 
San  Bernardino  range.  The  Colorado  desert  is  in  simjole  terms  the 
northern  portion  of  the  dej)ressed  area  occupied  by  the  Gulf  of 
California.  It  has  been  gradually  cut  off  from  the  gulf  by  the 
delta  material  brought  down  by  the  Colorado  river.  The  lowest 
portion  at  Salton  lies  260  feet  below  the  level  of  the  sea.  A  j^or- 
tion  of  the  Colorado  river  during  stages  of  high  water  is  frequently 
diverted  thru  a  channel  known  as  New  river.  This  latter  river 
runs  northerly  and  if  the  water  is  sufficient  reaches  the  Salton 
basin,  forming  a  broad  and  shallow  lake.  It  cannot  have  been  a 
very  long  joeriod  since  the  basin  was  occupied  by  a  permanent 
sheet  of  water,  for  the  old  shore  lines  are  very  distinct.  Extensive 
salt  works  are  situated  at  Salton,  the  salt  being  scraped  up  from 
the  deposit  covering  the  surface  of  the  basin. 

The  area  of  the  Mojave  desert  is  somewhat  triangular  in  sliape. 
It  is  between  200  and  )500  miles  wide  from  north  to  south  along  the 
eastern  border  of  the  state,  but  gradually  narrows  westward  as  the 
Sierra  Nevadas  and  Sierra  Madre  approach  each  other,  and  termi- 
nates at  their  meeting  point.  The  area  is  sharply  marked  off  upon 
the  south  by  the  Sierra  Madre  mountains,  but  upon  the  north  the 


14  THE    PHYSIOGRAPHY   OF    CALIFORNIA 

irregular  ranges  gradually  give  place  to  the  north  and  south  fault 
ranges.  This  region  is  hot  and  exceedingly  arid  except  toward  the 
western  end,  where  a  portion  known  a^  Antelope  valley  receives 
some  rainfall. 

Many  lake  basins  dot  the  surface  of  the  Mojave  desert.  Dur- 
ing the  Glacial  period  these  were  filled  with  shallow  bodies  of 
water,  but  now  they  are  dry  and  expose  vast  stretches  of  yellow 
clay.  The  only  stream  which  penetrates  the  desert  is  the  Mojave 
river.  It  rises  upon  the  northern  slojDe  of  the  San  Bernardino 
range  and  finally  sinks  in  the  center  of  the  desert. 

The  most  impressive  feature  of  this  region  is  that  of  the  long 
waste  slopes  which  center  about  the  scattered  mountain  peaks  and 
slope  away  for  miles  in  every  direction,  terminating  ujDon  the 
borders  of  the  ancient  lake  beds.  Over  wide  stretches  the  moun- 
tains have  nearly  disai^peared  beneath  these  waste  slopes,  rising 
only  as  small  rocky  knobs  browned  under  the  influence  of  the 
intense  heat  of  summer.  Toward  the  eastern  edge  of  the  area  there 
are  higher  mountains,  but  the  waste  slopes  are  fully  as  prominent. 
Pilot  knob  reaches  a  hight  of  5,500  feet,  but  the  most  of  the  val- 
leys vary  between  1,800  and  2,500  feet. 

The  topography  illustrates  most  excellently  the  conditions 
which  flnally  arise  in  the  course  of  the  degradation  of  a  mountain- 
ous region  from  which  the  waste  cannot  be  removed  l)ecause  of  the 
lack  of  an  outlet.  It  also  illustrates  the  effects  produced  by  erosion 
in  an  arid  climate.  What  little  niiu  there  is  comes  in  sudden  and 
severe  storms  at  rare  intervals.  The  rush  of  water  sweeps  the 
debris  from  the  mountain  canons  out  upon  the  valleys  at  their 
mouths.  There  the  waters  no  longer  confined  spread  out  and  drop 
their  load  in  the  form  of  debris  fans  or  cones.  These  coalescing 
when  the  canons  are  near  together  give  rise  to  the  long  and  gentle 
slopes. 

The  immense  quantities  of  fragmental  and  rudely  stratified 
material  forming  the  even  slopes  clustered  about  the  peaks,  and 
leading  down  to  the  inclosed  basins  or  sinks,  impresses  one  with  the 
power  of  the  destructive  agents.  Ev(>ryw]iere  the  desert  seems  a 
region  of  waste  and  desolation. 

Recent  volcanic  action  has  occurred  at  a  number  of  points. 
Finely  shaix'd  lapilli  cones,  and  long  winding  flows  of  black  basaltic 
lava  free  from  soil  and  unmodified  l)y  erosion,  are  characteristic 
forms. 


THE    rilYSKXiKAl'HV    OF    CALlFoKNlA  15 

Till'  lake  basins  upon  the  northern  od^o  of  the  area  were  sup- 
plied ilurin^  the  Glacial  period  with  water  from  the  melting  snows 
upon  the  Sierra  Nevada  mountains.  The  great  Borax  marsh,  whose 
surface  is  now  whitened  almost  as  far  as  the  eye  can  reach  by  the 
efflorescence  of  different  salts  from  the  moist  clays  beneath,  was 
then  occupied  l)y  one  of  these  lakes.  The  marsh  is  partly  inclosed 
by  mountains  upon  whose  sIojdcs  are  still  well  defined  beach  lines 
of  the  ancient  lake. 

We  pass  by  degrees  from  the  structureless  region  of  old  topo- 
graphic forms  to  that  upon  the  north,  where  the  north  and  south 
fault  lines  give  place  to  rugged  and  often  youthful  forms.  At  the 
southern  portion  of  the  latter  region  are  the  Panamint,  Amaragosa, 
Coso,  and  Slate  ranges.  The  highest  of  these  is  the  Panamint, 
which  at  one  point  reaches  an  elevation  of  10,000  feet.  These 
mountains  do  not  occur  as  isolated  blocks,  but  sending  oflP  s^jurs 
interlace  so  as  to  give  rise  to  valleys  more  or  less  separated  from 
each  other.  The  mountains  rise  to  a  hight  sufficient  to  give  them 
a  light  rain  or  snowfall  and  are  covered,  about  their  summits,  with 
a  scanty  growth  of  nut  pine.  There  is  scarcely  any  precijDitation 
in  the  valleys  but  occasional  springs  occur  near  the  edges  of  the 
valleys.  They  are  undoubtedly  connected  with  the  fault  fissures. 
Death  valley  is  the  most  widely  known  of  all  these  depressions.  It 
has  a  length  of  about  fifty  miles  and  a  width  of  ten.  The  center  of 
the  valley  lies  below  the  level  of  the  sea.  The  great  stretches  of 
alkali  flats  in  this  valley  acquire  an  intense  heat  during  the  sum- 
mer days,  and  have  proved  disastrous  to  many  a  prospector. 

Panamint  valley,  upon  the  opposite  side  of  Panamint  range 
fi'om  Death  valley,  is  nearly  as  large,  but  has  an  elevation  of  1.300 
feet.  Farther  west  and  across  the  Argus  range  is  Salt  Wells  des- 
ert, reaching  up  to  the  base  of  the  Sierra  Nevada  mountains.  The 
waste  slopes  in  some  of  these  valleys  have  spread  out  so  far  as  to 
nearly  or  quite  ol)literate  the  alkali  beds  of  the  former  lakes. 

Toward  the  southern  end  of  the  area  under  discussion  the 
mountain  slopes  are  more  dissected  and  do  not  show  such  marked 
indications  of  recent  movement.  To  the  north,  however,  lies  the 
Inyo- White  mountain  range,  having  a  length  of  nearly  100  miles. 
Thruout  much  of  its  length,  especially  upon  its  eastern  side, 
this  mountain  block  presents  a  fault  scarp  nearly  as  high  and  fully 
as  precipitous  as  that  of  the  Sierra  Nevada  mountains.  I'pon  the 
western  border  of  Saline  vallev.  which   lies   at   the  eastern  base  of 


16  THE    PHYSIOGRAPHY   OF    CALIFORNIA 

the  Inyo  ran^e,  the  hitter  apiDears  to  have  undergone  marked  eleva- 
tion in  very  recent  times.  The  borax  marsh  in  the  bed  of  the 
valley  lies  close  under  the  bold  eastern  front  of  the  range.  The 
disj^lacement  here  must  be  l)et\veen  8,000  and  10.000  feet. 

Owens  valley  is  one  of  the  most  interesting  basins  of  eastern 
California.  It  occupies  the  enormous  sunken  area  lying  between 
the  Sierra  Nevada  range  and  the  Inyo- White  mountain  range.  At 
the  southern  end  of  the  valley  is  Owens  lake,  one  of  the  largest  of 
the  remaining  basin  lakes  of  California.  It  has  an  elevation  of 
3,700  feet  and  lies  close  under  the  fault  scarp  of  the  Sierra  Nevada 
range.  The  depressed  crustal  block,  or  rather  blocks,  forming  the 
valley  extend  northerly  from  the  lake  for  about  80  miles  with  a 
width  of  10  miles.  Owens  river  traverses  the  valley,  rising  in  the 
Sierras  opposite  its  northern  end  and  emptying  into  the  lake. 
Many  small  streams  enter  the  valley  from  the  west  and  are  used 
for  irrigation.  How  completely  the  Sierras  cut  off  the  moist  winds 
is  shown  by  the  fact  that  altlio  the  Inyo  and  White  mountain 
ranges  in  places  rise  nearly  as  high,  yet  the  precipitation  upon 
them  is  very  light. 

During  the  high  water  stage  of  the  Grlacial  period  Owens  lake 
overflowed  its  basin.  The  waters  poured  thru  the  long  depression 
extending  southerly  from  the  lake  and  close  under  the  Sierras,  and 
passing  the  narrow  gap  where  the  Coso  mountains  come  so  close 
to  the  Sierras,  emptied  into  Salt  Wells  desert.  From  the  latter 
region  they  spread  to  the  borax  marsh  already  described.  The 
ancient  bed  of  this  now  dry  river  corresponds  in  liight  to  the 
uppermost  terrace  of  Owens  lake.  The  river  was  fully  1,000  feet 
wide  and  its  ancient  channel  is  now  followed  for  thirty  miles  by 
the  wagon  road  from  Mojave  to  Owens  valley. 

Running  thru  the  middle  of  the  Owens  valley  depression  and 
toward  its  southern  end  there  is  a  line  of  hills  called  the  Alabama 
hills.  These  have  an  abrupt  front  to  the  east  rising  200-300  feet 
above  the  sandy  river  bottom.  This  shows  that  the  valley  is  divided 
into  at  least  two  longitudinal  blocks,  the  eastern  one  having  been 
dropped  more  than  the  other.  As  a  feature  of  the  earthquake  of 
1872  a  new  fault  line  w^as  formed  in  the  valley  near  this  scarp,  the 
valley  drojjping  10-40  feet  more. 

Volcanic  flows  and  cinder  cones  mark  the  line  of  displacement 
in  Owens  valley  at  several  points.  North  of  the  town  of  Bishop 
at  the  upper  end  of   the   valley  a  broad    tal)le   land  of  volcanic  ash 


THE  I'I1Vsio(;i;aimin    oi'  cai-H'oknta  17 

commcHfcs  niul  cxtciids  iii.niy  miles  in  llic  direction  of  Mono  lake. 
Tlio  tal)]e  land  .gradually  rises  to  a  low  divide  and  is  then  replaced 
by  low  rid,(:;es  of  rhyolitic  lavas,  between  which  are  extensive  plain- 
like valleys  covered  with  loose  volcanic  ashes. 

Owens  river  has  cnt  a  canon  thru  this  plateau  fully  l.OOO  feet 
deep.  Alonii-  the  snnnnit  of  the  valley,  between  Owens  valley  and 
Mono  lake,  the  lavas  have  been  i)iled  up  so  as  to  nearly  ol)literate 
the  fanlt  scarp.  As  we  approach  Mono  lake  it  a,u-aiii  conies  out 
very  boldly,  and  at  the  lake  the  fault  scarj).  tho  nmch  eroded,  is 
about  5,000  feet  hi.u'h.  The  settlin.L^  of  the  basin  in  wliich  Mono 
lake  lies  has  forced  the  water  close  up  nnder  the  scarp.  Here  also 
a  recent  movement  has  occurred,  as  shown  at  the  mouth  of  Mill 
canon  by  a  wall  of  earth  40  feet  hii^h. 

The  region  about  Mono  lake  has  been  tho  theater  of  many 
volcanic  outbreaks  and  earthquake  disturbances.  The  islands  in 
the  lake  are  fissured  and  shattered,  while  upon  the  north  shore  of 
the  lake  at  Black  point  there  are  open  earthquake  fissures. 

Extending-  south  of  the  lake  for  a  distance  of  10  miles  there  is 
a  t;-roup  of  remarkable  volcanoes  known  as  the  Mono  craters.  These 
have  been  formed  thru  the  jnlin^  up  of  viscid  lavas  and  vastcpian- 
tities  of  pumiceous  ash.  There  are  craters  here  formed  ])y  explo- 
sions merely,  by  the  piling  up  of  ashes  about  an  orifice,  and  by  the 
upwellino-  of  viscid  lavas.  Several  of  the  craters  from  which 
pumice  was  at  first  blown  were  afterward  the  scene  of  outpouring; 
lava.  In  two  or  more  instances  the  lava  cooled  l)efore  overfiowinii" 
the  older  crater  of  asli.  These  features  have  been  unaffected  by 
erosion  and  remain  almost  as  perfect  as  when  formed,  makini;-  the 
region  one  of  exceptional  interest. 

The  waters  of  Mono  lak<'.  like  those  of  Owens  lake,  are 
intensely  alkaline.  Judging  from  the  terraces,  the  lake  did  not 
overflow  its  basin  during  the  Glacial  period. 

For  some  distance  north  of  Mono  lake  the  fault  scarp  of  the 
Sierras  is  less  bold  and  the  region  is  largely  covered  with  andesitic 
lavas.  In  these  lavas  occur  the  noted  gold-sliver  deposits  of  Bodie. 
Continuing  toward  Lake  Tahoe  w^e  cross  the  valleys  of  the  Walker 
and  Carson  rivers,  which  near  thv  mountains  are  well  watered  and 
highly  cultivated.  After  traversing  a  nund)er  of  valleys  the  Walker 
river  empties  into  Walker  lake  and  the  Carson  spreads  out  in  a 
sandv   waste   kjiown    as    the  Siuk    of    the   Carson   in  west   central 


18  THE    T'HYSIOC.HAI'HV    OF    CALIFORNIA 

Nevada.     The  Carson  valley  just  over  the  liiu>  in  Nevada  is  one  of 
the  lar^•est  and  most  fertile  of  the  farniino-  regions  of  Nevada. 

Lake  Tahoe  has  already  been  deseril)ed  in  connection  with  the 
Sierra  Nevada  mountains,  altho  its  drainage  thru  the  Truckee  river 
is  into  the  (Ireat  l^asin.  This  lake,  with  an  elevation  of  0,225  feet, 
but  200  mort!  than  Mono  lake,  is  a  sheet  of  pure  cold  water,  con- 
trasting strongly  with  the  latter. 

During  the  Glacial  period  a  great  lake  called  Lahontan  spread 
over  the  now  desert  basins  of  northwestern  Nin'ada  and  into  the 
edge  of  California.  A  large  remnant  of  this  lake  remains  to  the 
present  day  at  the  foot  of  the  fault  scarp  in  northeastern  Califor- 
nia. This  body  of  water  is  known  as  Honey  lake  and  has  an  eleva- 
tion (jf  about  4,000  feet.  At  present  it  has  no  outlet  and  is  of 
c-ourse  alkaliiu". 

The  Volcacic  Plateni  Region.  The  northeastern  part  of  Cali- 
fornia is  ail  extensiv(^  plateau  region  broken  by  numerous  ranges 
of  mountains.  Under  the  above  head  wnll  l)e  discussed  all  that 
area  lying  east  of  a  line  connecting  Shasta  valley  with  the  north- 
ern end  of  the  Sierra  Nevada  mountains.  The  Lassens  peak  ridge 
and  the  line  of  extinct  volcanoes  reaching  north  to  Mount  Shasta 
and  connecting  with  the  Cascade  range  of  Oregon  have  been 
included  l)y  some,  and  jaerhaps  justly,  in  the  Cascade  range.  The 
volcanic  peaks  undoubtedly  do  form  a  continuation  of  those  of  the 
Cascade  range  in  Oregon,  but  thru  northern  California  this  range, 
aside  from  the  scattered  peaks,  can  scarcely  be  distinguished  from 
the  volcanic  plateau  region  to  the  east.  It  is,  in  fact,  continuous  with 
that  plateaii. 

The  plains  and  valleys  of  this  region  have  an  elevation  of  8,300 
to  5,000  feet,  while  some  of  the  mountains,  exclusive  of  the  volcanic 
peaks,  attain  a  liight  of  10,000  feet.  The  region  is  made  up  almost 
wholly  of  volcanic  rocks,  and  is  structurally  as  well  as  historicall}^ 
closely  rehited  to  the  northern  portion  of  the  Great  Basin  and  the 
plateau  region  of  eastern  Oregon. 

I'he  greater  portion  of  the  area  is  fairly  well  watered,  for  the 
moiiiit.iiiis  on  the  west  are  not  high  enough  to  cut  otf  the  moist 
winds  from  the  Pacific.  Irrigation  is,  however,  often  resorted  to, 
and  in  the  extreme  northeastern  \r,\vt  the  long  fertile  valley  known 
as  Surprise  valley  is  largely  dependent  upon  irrigation. 

Nmnerous  lakes,  some  of  them  of  large  size,  are  scattered  over 
this  region,     They  are  reiniuviits  of  much  larger  ones  of  the  early 


THE    rTIYSIOORAPHY   OF    CALIFORNIA  19 

part  of  the  Pleistocene  period.  Upon  the  borders  of  tlie  area  are 
several  lakes  without  outlet,  which  mi<j;ht  properly  be  included  in 
the  area  of  the  Great  Basin.  These  areTule  lake  upon  the  borders 
of  Ore<i;{)n.  aiid  tlie  Surprise  valley  lakes. 

Th(»  major  portion  of  the  area  is  drained  by  Pitt  river,  tin; 
most  important  tributary  of  the  upper  Sacramento.  Many  of  the 
valleys  which  Pitt  river  traverses,  such  as  Fall  River,  were  once 
occuj)ied  by  lakers.  The  lakes  were  finally  drained,  partly  perhaps 
as  a  result  of  mountain  movements,  and  jjartly  thru  stream  action. 
Pitt  river  in  its  ujjper  course  passes  alternately  thru  broad 
plain-like  valleys  and  deep  canons.  The  lake  of  Fall  River  valley 
had  apparently  no  very  hi<>-h  barrier  upon  the  west.  The  lowest 
portion  of  this  barrier  is  now  traversed  by  Pitt  river  in  a  f^orge  of 
considerable  dejjth  and  ruggedness.  The  extreme  source  of  this 
river  has  be(ni  Goose  lake,  a  lar*i;e  l)()dy  of  water  lyinu;  partly  in 
Oreg-on,  but  at  the  present  time  the  waters  of  the  lake  seldom  rise 
sufficiently  to  cause  an  overflow. 

The  Surprise  valley  lakes  are  shallow,  and  during-  some  seasons 
almost  wholly  dry  up.  Eagle  lake,  in  the  southern  portion  of  the 
area,  has  no  surface  outlet,  but  there  must  be  one  underground,  for 
the  water  is  perfectly  pure. 

Tule  or  Rhett  lake  is  interesting  in  many  respects.  It  together 
with  the  Klamath  lakes  formed  one  large  body  of  water  until  Kla- 
math river  cut  its  present  canon  and  partly  drained  the  old  basin. 
Tule  lake  now  has  no  surface  outlet,  but  the  waters  are  fairly  fresh. 
Klamath  river  during  stages  of  high  water  has  until  recently  been 
partly  diverted  to  Rhett  lake,  but  this  no  longer  haj)pens.  The 
region  about  the  lake  is  (piite  arid  and  few  streams  enter  it. 

Interesting  drainage  features  are  associated  with  the  recent 
extensive  flows  of  lava.  In  such  areas  there  is  generally  little  sur- 
face water,  but  underground  streams  are  frequent.  Rugged  lava 
fields  stretch  from  Tide  lake  south  into  the  upper  end  of  Fall  River 
valley.  Much  of  this  lava  at  least  was  formed  since  the  lake  period 
and  altho  vegetation  has  gained  a  foothold  upon  its  surface,  yet 
the  rocks  are  quite  free  from  soil  and  exceedingly  rough.  The 
surface  of  the  flow  contrasts  strongly  with  the  deep  soil  and  heavy 
forests  about  it.  Fall  river  bursts  out  in  numerous  large  springs 
from  beneath  the  end  of  the  lava  flow,  and  after  winding  sluggishly 
thru  the  valley  for  15  miles  enters  Pitt  river  thru  a  series  of  swift 
rapids.     The  river  has  a  very  snudl  local  drainagt>  and  never  varies 


20  THE    I'll  VSKHiIJA  I'll  V    OF    CALIFORNIA 

in  size  between  winter  ;iii(l  smniner.    Ifat  ereek  is  a  similar  stream, 
which  eiitiTS  Pitt  I'iver  from  the  direction  of  Lassens  i^eak. 

The  mountains  risintj;  from  this  plateau  region  are  mostly  due 
to  one  of  two  causes,  either  th(>  i)ilinLi-  u])  of  eruptive  material  or 
faultiiiL;-.  The  ])hysioL!,-raphic  liistoiw  lias  certaiidy  been  a  compli- 
cated one.  The  older  mountains  of  the  region  exhibit  no  reo'ular 
arrane-ement  and  have  been  much  modified  by  erosion.  The  War- 
ner niomitaiiis  bounding-  Surprise  valley  upon  the  west  constitute 
the  l)est  example  of  the  (Ireat  Basin  type  of  elevations  in  north- 
eastern California.  Th(\y  extend  north  and  south  for  about  70 
miles,  risine-  to  about  lO.OOO  feet  elevation  in  the  highest  i^ortion. 
They  present  a  bold  scarp  to  the  east  and  a  font;-  gentle  slope  upon 
the  west.  This  fault  scarp  has  been  deeply  sculptured  by  erosion, 
and  owiiiu;  to  the  tutfaceous  character  of  a  portion  of  the  lavas  of 
which  it  is  composed,  often  presents  picturesque  castellated  forms. 

Recinit  fault  movements  appear  to  have  taken  place  along  the 
base  of  the  Warner  range.  The  features  produced  by  similar  move- 
ments are  to  be  found  over  many  other  portions  of  this  plateau 
region.  These  consist  of  long  lines  of  bluffs  extending  northerly 
and  southerly  with  scarps  100  to  200  feet  high.  These  perhaps 
more  fre([uently  face  the  west  and  traverse  all  but  the  most  recent 
of  the  lavas. 

The  volcanic  rocks  of  the  greater  portion  of  this  plateau  region 
have  undoubtedly  issued  in  a  molten  condition  from  fissures  in  the 
crust  and  not  from  definite  centers  like  those  which  result  in  vol- 
canic peaks.  The  line  of  great  volcanic  peaks  stretching  from  the 
northern  end  of  the  Sierra  Nevada  range  no7-tliward  into  Oregon 
grew  up  toward  the  close  of  the  long  jjeric^d  of  igneous  action, 
probably  in  the  later  Pliocene.  They  undoubtedly  vary  in  age  and 
have  time  and  again  been  modified  by  new  eruptions.  Some  are 
greatly  dissected  by  erosion  while  others  are  comparatively  intact. 

Under  the  gre;iter  peaks  we  will  include  Mt.  Lassen,  Crater 
peak,  Magee  peak.  P)urney  butte  and  Mt.  Shasta.  Lassen  peak 
rises  to  a  liight  of  10,437  feet  and  is  the  center  of  an  exceedingly 
interesting  volcanic  region.  Cinder  cone,  a  little  to  the  northeast, 
was  the  scene  of  what  was  pro])ably  the  most  violent  volcanic  erup- 
tion in  ( ',ilif(u-nia.  Judging  from  the  tree  trunks  still  standing  in 
a  fiekl  of  volcanic  ashes,  this  eru])1ion  could  not  have  been  more 
than  two  hundred  years  ago. 


THE    I'HVSI()(ii;AI'll\     Ol-    (  AI.II'dKNIA  21 

Blimey  Imtte  is  the  most  perfect  of  the  lariiicr  volcjiiiic  peaks. 
It  rises  to  a  lu,i,^ht  of  7,880  feet. 

Mount  Shasta  reaches  an  elevation  of  14,350  feetbein*^  next  to 
Rainier,  the  loftiest  peak  of  the  Cascade  range.  Tho  l)ut  a  little 
lower  than  Mt.  Whitney  it  presents  a  far  more  iniposint^  appear- 
ance owing  to  the  low  mountains  and  open  valleys  which  surround 
it.  Strawberry  valley  at  its  southwestern  base  has  an  elevation  of 
8,550  feet  and  from  this  valley  as  well  as  from  others  upon  the  west 
and  south  the  mountain  presents  an  appearance  so  striking  and 
grand  that  when  once  seen  it  can  never  be  forgotten.  Its  summit, 
snow  covered  tliru  the  year,  with  the  dark  forest  encircling  it  below, 
is  ever  a  feature  of  fascinating  interest.  Since  the  glacial  period, 
lavas  have  issued  from  its  sides,  and  one  stream  flowed  for  more 
than  fifty  miles  down  the  canon  of  the  Sacramento  river.  Small 
glaciers  still  remain  in  sheltered  depressions.  The  melting  snows 
furnish  water  for  a  number  of  underground  streams  which.break  out 
in  the  canons  of  the  Sacramento  and  McCloud. 

To  the  west  of  Shasta  there  rises  a  very  perfect  cone  known  as 
Sugar  Loaf  or  Black  butte.  It  towers  over  2,000  feet  above  the 
valley. 

In  addition  to  the  great  volcanoes  already  described  there  are 
hundreds  of  smaller  ones  scattered  over  this  region.  The  large  vol- 
canoes have  been  built  up  thru  a  combination  of  massive  flows  and 
fragmental  material  blown  out.  The  smaller  ones  are  almost  all 
lapilli  cones  and  generally  do  not  rise  more  than  100  to  500  feet. 
They  have  steep  slopes  and  crater-like  depressions  in  their  tops. 
They  represent  the  last  expiring  forces  of  tlu^  volcanic  period. 

THE   GREAT    VALLEY 

The  Great  Valley  of  California  lies  in  the  very  heart  of  the 
state  and  is  entirely  enclosed  by  mountains  save  at  the  narrow  out- 
let thru  which  its  drainage  passes.  The  valley  is  practically  a  vast 
plain  about  four  hundred  mih^s  long  and  fifty  miles  wide.  The 
San  Joaquin  river  with  its  tributaries  drains  the  southern  arm  antl 
the  Sacramento,  the  northern.  These  streams  unite  a  little  north 
of  the  central  portion  of  the  valley  in  a  region  of  lowlands  and 
marshes  and  pour  their  united  volume  thru  the  straits  of  Karquines 
into  San  Francisco  bay.  Tlu'  two  arms  of  the  Great  Valley  rise 
very  gently  towards  their  extremities  where  they  attain  an  elevation 
of  not  much  over  live  hundred  feet.     Much  of  the  lower  portion  of 


22  THE    PHYSIOGRAPHY    OF    CALIFORNIA 

the  vjillt'v  Iviiit;-  west  of  ;i  line  connecting  Sacramento  and  Stockton 
is  tioodcd  (luriiiiA-  the  sprin^-  rise  in  the  streams.  As  a  result  of  the 
recent  coastal  snlnners^ence  much  of  this  marshy  land  is  subject  to 
tidal  iiiHueiice.  the  tides  beinj^  felt  many  miles  up  the  sluggish 
streams.  Al)out  Martinez  the  flat  bottomed  alluvial  valleys  with 
the  abruptly  rising  hills  also  support  the  view  of  a  subsidence  of 
the  region  about'tlie  outlet  of  the  (Ireat  Valley. 

Owing  to  the  light  grade  and  the  large  amount  of  material 
offered  for  transportation,  some  of  the  streams  flow  upon  channels 
elevated  al)ove  the  surrounding  country.  For  many  miles  the 
Sacrameiiio  river  is  bordered  by  narrow  banks  of  dry  land  behind 
whicli    an'   large  stretches  of  marsh  and  overflow   land. 

The  moist  winds  from  the  ocean  pass  inland  across  the  Coast 
Raiiues.  so  that  the  eastern  slopes  of  the  latter  receive  much  less 
rain  than  the  western.  The  Sierra  Nevada  mountains  being  higher 
than  the  Coast  Ranges,  their  western  slope  is  well  watered  while 
the  streams  are  nuiintaint^l  thru  the  summer  by  the  melting  snows. 
As  a  result  of  these  conditions  only  few  permanent  streams  enter 
the  Great  Valley  from  the  west,  and  these  are  confined  to  the 
northern  portion  known  as  the  Sacramento  valley.  The  southwest- 
ern portion  of  the  San  Joaquin  receives  a  very  scanty  rainfall. 

Tlie  Creat  Valley  occupies  a  structural  depression  of  consider- 
able geological  age.  The  greater  portion  has  either  been  near  the 
sea  level  or  beneath  it  for  long  periods  of  time  while  the  surround- 
ing mountains,  particularly  the  Coast  Ranges  have  undergone  fold- 
ing and  faulting. 

The  sui-face  of  the  valley  is  in  part  formed  of  delta  deposits, 
of  the  present  streams,  of  recent  lake  beds,  and  of  the  slightly 
eroded  surface  of  uplifted  beds  of  Pliocene  age.  The  floor  of 
tlu^  valley  ])lends  imperceptibly  in  many  places  thru  the  foothills 
into  the  anci(mt  peneplain  of  the  Sierra  Nevada  mountains.  Upon 
the  Coast  Rang(^  side  the  mountains  rise  more  abruptly,  and  in  the 
San  Joaquin  valley  in  particular  tlun-e  are  long  waste  slopes  built 
up  by  the  action  of  th(^  wet  weather  streams. 

Along  the  eastern  edge  of  the  central  portion  of  the  Ureat  Val- 
ley the  streams  are  large  and  have  cut  down  slightly  into  the 
stratifi.id  sedimentary  deposits  of  an  earlier  depression.  Waste 
slopes  and  delta  deposits  nrv  not  prominent.  Farther  south  how- 
ever w(>  find  that  the  Kings  and  Kern  rivers  have  formed  large  del- 
tas which  liave  considerably   modified  the   surface  of  the  valley. 


THE    PHVSKXVHAI'HY    OF    CAI.IFOKXIA  '2'A 

All  L'xaniiiiatioii  of  ;i  relief  map  of  California  will  sIkav  that  tlie 
San  Joaquin  river  lies  inucli  nearer  the  coast  raii<;es  than  it  does 
the  Sierras.  The  ,<i;reater  watershed  upon  the  east  as  well  as  vol- 
ume  of  water  and  the  large  amount  of  waste  brouf^ht  from  that 
direction  have  forced  the  river  to  the  western  side  of  the  valley, 
The  delta  of  Kint^s  river  has  been  extended  across  the  valley  so  as 
to  form  an  inclosed  basin  of  the  southern  portnon,  from  which 
there  is  overflow  only  in  seasons  of  exceptional  rainfall.  This  gave 
rise  to  Tulare  lake,  a  large  body  of  shallow  water.  With  the 
increase  of  land  cultivation  and  use  of  water  in  irrigation  the  lake 
is  gradually  disappearing.  Kern  and  Buena  Vista  lakes  are  smaller 
bodies  of  water  lying  to  the  south.  They  are  fed  by  Ki^rn 
river  chiefly  and  are  dry  during  some  seasons.  The  delta  of  the 
Kern  river  is  dotted  with  cottonwood  trees  for  miles,  and  altho 
formed  of  sandy  material  is  very  productive  under  irrigation. 

The  San  Joaquin  valley  is,  as  a  rule,  destitute  of  trees  except 
for  fringes  along  the  streams,  but  large  portions  of  the  Sacramento, 
receiving  a  greater  rainfall  are  dotted  with  oaks.  The  accumula- 
tion of  material  in  the  Grreat  Valley  in  recent  times  is  enormous. 
Well  borings  in  the  center  of  the  valley  show  that  it  is  filled  to  a 
depth  of  more  than  two  thousand  feet  with  gravel  and  clay  of  lake  or 
liuvatile  origin.  Remains  of  trees  and  land  animals  of  Pleistocene 
age  have  been  found  in  these  deposits.  The  valley  has  either  been 
the  scene  of  delta  accumulation  al)ov(^  water  as  at  present,  or  its 
siirface  has  been  occupied  by  a  body  of  fresh  or  salt  water.  It  is 
quite  probable  that  at  one  time  in  its  geological  history  tlit^  outlet 
was  to  the  south  instead  of  west  as  at  present. 

We  find  the  old  peneplain  already  referred  to,  particularly  well 
developed  upon  the  borders  of  the  upper  Sacramento  valley.  This 
plain  is  not  now  continuous  with  that  extended  over  much  of  the 
Klamath  mountains  probably  because^  of  deformation  which  has 
occurred  since.  The  streams  which  enter  the  Sacramento  from 
the  Klamath  mountains  have  cut  canons  thru  the  plain.  l)ut  it  is 
nevertheless  a  striking  feature  of  the  landscape. 

The  Feather  river,  one  of  the  largest  tributaries  of  the  Sacra- 
mento, has,  since  hydraulic  mining  has  been  carrieMl  on.  built  up  its 
bed  to  such  a  degree  that  it  is  now  higher  than  the  streets  of 
Marysville  and  has  to  be  restrained  by  levees. 

The  only  marked  elevation  in  the  whole  of  the  region  under 
discussion  is  found  in  tlu^  center  of  tlie  Sacramento  vallev  west  of 


24 


Tin:    I'llVSIOdRAPHY    OF    CALIFOHNIA 


Marysvillc.  It  is  known  as  the  Marysville  buttes.  Here  is  a 
Ljroiip  of  serrated  and  i)ictnresque  peaks  rising  about  two  thous- 
and feet  above  the  level  and  monotonous  valley.  They  ai*e  known 
as  the  Marysvillc  hnttcs  and  represent  a  deeply  dissected,  volcano 
of  late  Tertiary  time. 

THE    COAST    KANCiES 

The  presence  of  a  continuous  line  of  mountains  along  the  coast 
of  California  has  already  been  referred  to.  These  mountains  are 
known  as  the  Coast  Kanges  or  Coast  Range  system.  As  the  name 
indicates,  they  are  not  made  up  of  one  dominant  axis,  but  of  sev- 
eral extending  side  by  side  and  often  having  broad  valleys  between 
them.     As  we  follow  tlu^n  northward  toward  the  40tli  parallel  this 


■:«^vv-     .^„0im 

1^^ 

:^^^0^'^ 

lil 

C.\JON    PASS   IX   THE  SAN   BERNARDINO   RANGE. 

composite  character  disap[)ears.  The  broad  valleys  give  place  to 
canons,  and  the  regular  mountain  ranges  to  a  broad  group  of  rugged 
and  irregular  mountains.  This  lattt>r  region,  lying  partly  in  Cali- 
fornia and  partly  in  Oregon  forms  the  Klamath  mountains.  No 
definite  limit  has  been  established  for  the  boundary  of  the  Coast 
Ranges  upon  the  north,  and  no  natural  one  can  be,  unless  it  is  upon 
geological  grounds,  for  the  Coast  Ranges  blend  gradually  into  the 
higher  and  more  rugged  regions  of  the  Klamath  mountains. 

T'])on  the  south  the  Coast  Ranges  may  be  considered  as  ter- 
minating at  the  point  where  they  meet  the  JSierra  Nevada  and  Sierra 
Madre  ranges.  Here  are  the  San  Emedio  mountains  the  highest 
15oint  of  which.  Mount  Pinos,  reaches  an  elevation  of  over  nine 
thousand  feet.  In  this  region  also  the  limit  placed  u[)on  the  appli- 
cation of  the  term  Coast  Ranges  is  merely  oneof  convenience.    The 


THE    PHYSIOGRAPHY    OF   CALIFORNIA  25 

Sierra  Madro  toticthcr  with  the  Peiiinsuhi  raii^e  of  southern  Cali- 
fornia lie  farther  l)aek  from  the  coast,  and  the  Sierra  Madre  in  par- 
ticular is  separated  from  it  by  a  complex  structure  of  lesser 
mountains. 

Thruout  the  most  of  their  length  the  Coast  Ranjjjes  have  a  very 
regular  northwest  and  southeast  direction  being  nearly  parallel 
with  the  coast.  The  slight  discrepancy  in  direction  between  shore 
line  and  mountain  range  has  given  rise  to  the  most  important  of 
the  shore-line  irregularities.  Where  a  mountain  range  comes  out 
to  the  ocean  there  is  a  more  or  less  prominent  cape,  while  between 
that  and  the  next  range  there  is  an  indentation  of  the  coast. 

Toward  the  southern  end  the  Coast  Ranges  change  their  course 
and  extend  more  nearly  east  and  west.  Point  Arguello  is  the  sea- 
ward termination  of  the  Santa  Ynez  range  and  marks  a  change  in 
the  direction  of  the  coast  line  corresponding  with  the  east  and  west 
structure  of  these  mountains. 

The  geological  structure  of  the  Coast  Ranges  is  exceedingly 
complex.  Repeated  folding  and  faulting  thru  a  long  period  of 
geological  time  have  followed  a  general  northwest  and  southeast 
direction.  The  structural  conditions  together  with  great  variations 
in  resistance  to  erosion  of  different  rock  formations,  and  the  fre- 
quent movements  of  the  land  as  a  whole  with  reference  to  the  ocean 
level,  have  given  us  the  complicated  topography  of  the  present  day. 

The  drainage  of  the  great  interior  region  of  the  state  passes 
directly  across  the  Coast  Ranges  thru  the  straits  of  Karquines, 
San  Pablo  and  San  Francisco  bays  to  the  ocean.  This  gap  in  the 
Coast  Ranges  with  its  tributary  valleys  does  not  appear  to  be  of 
structural  origin  but  to  represent  what  was  a  depression  or  sag  in 
the  Coast  Ranges  subsequently  enlarged  by  the  concentration  of 
the  drainage  lines. 

Thru  the  ctnitral  Coast  Ranges  we  cannot  trace  the  same 
ancient  ixnieplain.  which  we  find  in  the  northern  Coast  Ranges, 
the  Klamath  and  Sierra  Nevada  mountains,  unless  it  be  in  more 
fragments  here  and  there.  The  important  structural  features  of 
the  Coast  Ranges  date  far  back,  but  diiferential  movement  in  recent 
geological  times  has  been  so  marked  as  to  mask  or  destroy  topo- 
graphic features  which  in  more  stable  regions  would  have  been 
preserved.     Some  of  the  mountain  axi'S  we  know  wi're  not  in  exist- 


20  THE    PITY^^TOGEArHY    OF    CALIFORNIA 

ence  even  as  late  as  the  Pliocene  period.  The  Berkeley  hills  now 
risin.fj  nearly  two  thonsand  feet  have  upon  their  summits  folded 
sediments  of  a  fresh  water  lake  of  late  Pliocene  age. 

Ill  tlu'  latitude  of  San  Francisco  bay  the  Coast  Kanges  appear  as 
three  well  defined  mountain  axes.  Upon  the  east  there  is  the 
T^Iount  Diablo  range  and  its  topographic  continuation  across  Sui- 
sun  bay  in  the  mountains  east  of  Napa  valley.  In  the  middle 
there  is  the  northern  prolongation  of  the  Mount  Hamilton  range 
corresponding  on  the  opposite  side  of  the  bay  to  the  mountain 
ridge  l)etween  Napa  and  Sonoma  valleys.  Upon  the  west  there 
is  the  Santa  Cruz  range  south  of  the  Golden  Gate  and  the  range  of 
which  Mount  Tamalpais  is  the  culminating  peak.  The  valley 
between  these  ranges  opening  out  to  San  Pablo  and  San  Francisco 
bays  are  among  the  most  fertile  and  highly  cultivated  in  the  state. 
The  Santa  Clara  valley  penetrated  by  the  southern  arm  of  San 
Francisco  bay,  and  the  Sonoma  valley  extending  northwest  from 
San  Pablo  bay  are  the  largest;  Napa  valley  comes  next  in  size. 
Sonoma  valley,  and  Santa  Clara  with  its  southeast  prolongation, 
the  San  Bcmito  valley,  are  each  nearly  one  hundred  miles  long  and 
attain  a  widtli  in  places  of  eight  to  twelve  miles.  Their  nearly 
level  bottom  lands  are  formed  of  sediments  deposited  in  long, 
narrow  estuaries  of  the  ocean  during  the  last  great  submergence  of 
th(^  coast.  All  about  th(-  bay  are  low  lands  sloping  gently  back  to 
the  surrounding  hills.  These  are  of  the  same  nature  as  the  valley 
floors  exc(^pt  for  some  modification  thru  stream  action.  The  bay 
is  shoaling  in  many  places,  and  since  the  last  submergence  giving 
rise  to  the  present  sheet  of  water  thousands  of  acres  have  been 
filled  in  with  stream  or  delta  deposits. 

The  hills  comedown  (luite  boldly  to  the  straits  of  Karquines, 
a  fact  whi<'li  would  be  explained  l)y  the  theory  of  a  clifPerential 
movement  of  the  mountains  with  reference  to  the  floor  of  the 
Great  valley. 

The  broad  valleys  of  the  San  Francisco  bay  region  cannot  be 
considered  other  than  structural  in  their  origin,  but  modified  and 
enlarged  by  erosion.  All  cannot  have  had  the  same  history.  The 
sharp  contrasts  between  the  canons  which  open  back  into  the 
enclosing  mountains  and  the  broad,  even-floored  valleys  would  in 
itself  suggest  that  the  one  is  new,  the  other  old. 


THE    I'lnSIOGKAl'HY    OF    CALIFORNIA 


27 


All  the  features  of  San  Francisco  bay  impress  one  as  those  of  a 
drowned  area.  As  the  land  sank  the  sea  came  in  thru  the  Golden 
Gate,  flooding  the  lower  portion  of  the  ^rcat  river.  The  character 
of  the  hays  and  islands,  and  especially  the  tilled  in  valleys  l^etween 

Sansalito  and  San  Rafael,  illustrate 
particularly  well  this  last  ijhase  of 
the  physiograijhic  history  of  this 
region. 

Mount  Diahlo  dominates  the 
outlet  of  the  Great  valley.  It 
rises  to  a  height  of  3,850  feet,  and 
is  by  far  the  most  prominent  and 
striking  feature  of  the  Coast 
l\anges  as  one  approaches  them 
across  tlie  Great  valley.  The  core 
of  this  mountain  is  made  wp  of  the 
older  rocks  of  the  Coast  Ranges 
((_iol(l(-ii  Gate  formation.)  Its 
prominence  is  due  in  part  to  oro- 
-rapliic  movements,  and  in  part  to 
the  more  rapid  erosion  of  the  sur- 
rounding beds. 

The  mountains  enclosing  Napa 
valley  as  well  as  a  considerable  portion  of  the  Coast  Ranges 
extending  north  to  Clear  lake,  are  of  volcanic  origin.  The  highest 
peak  of  this  volcanic  region  lies  northwest  of  Napa  valley.  It  is 
known  as  St.  Helena  and  attains  an  elevation  of  4,300  feet. 

As  we  go  northwesterly  from  San  Francisco  bay,  the  valleys 
become  narrower  and  the  mountains  higher.  Near  the  coast  there 
are  heavy  forests  of  redwood,  but  farther  inland  the  mountains 
become  less  timbered  while  the  valleys  are  dotted  with  oaks. 

About  one  hundred  miles  north  of  San  Francisco  and  within 
the  heart  of  the  Coast  Ranges,  lies  Clear  lake.  It  is  an  irregular 
lake  with  a  length  of  aboiit  twenty-five  miles  and  an  elevation  of 
1,310  feet.  It  is  the  only  lake  of  any  size  within  the  Coast  Ranges. 
The  surrounding  region  was  the  scene  of  protracted  volcanic  action 
during  the  Pliocene  period.  Uncle  Sam,  a  bold  and  picturesque 
mountain  of  volcanic  origin,  overlooks  the  lake  and  rises  to  a 
height  of  4,200  feet.  Mineral  springs  of  many  kinds  abound  in 
this'section,  and  at  the  Sulphur  Bank  near  the  eastern  end  of  the 


A  YOUNG  CANYON  IN  THE  SIERRAS. 


28 


THE    PHYSIOGRAPHY    OF    CALIFORNIA 


lake,  there  is  a  most  inten^stin^  example  of  solfataric  action  with 
deposits  of  sul})huran(l  eimiabar. 

The  \vat(>rs  of  Clear  laki;  now  empty  thru  Cache  creek  at  its 
eastern  end  into  the  Sacramento  river.  The  ontlet  of  the  lake  was 
formerly  westward  thrn  the  canon-lik(^  depression,  in  which  the 
pictnrescpie  B1ik»  lakes  lie,  into  a  tributary  of  Eussian  river.  Only  a 
few  feet  rise  of  the  waters  of  Clear  lake,  would,  if  the  eastern  outlet 
were  stopped,  a<2;ain  send  th(i  draina<4e  of  the  lake  westward  directly 
to  the  ocean.  The  cause  of  the  chanij;e  of  drainage  has  not  been 
investigated.  It  may  have  been  due  to  a  tilting  of  the  mountains 
or  thru  a  lowering  of  the  divide  of  Cache  creek  by  erosion. 


THE  NEliULES— Showing  one  type  of  Weathering. 

North  of  Clear  hike  the  Coast  Ranges  form  practically  a  unit. 
There  are  but  two  slopes,  a  short  one  toward  the  east,  and  a  long 
one  westward  to  the  Pacific.  The  crest  gradually  rises  as  we  fol- 
low it  northward,  until  in  the  Yallo  Bally  peaks  it  reaches  a 
height  of  aliont  8,000  feet.  The  main  stream  draining  the  western 
slope  in  this  section  is  Eel  river.  This  stream  and  its  tributaries 
exhibit  a  fairly  well  matured  stage  of  development.  The  courses 
of  the  large  streams  are  mostly  subsequent,  altho  they  still  flow 
thru  canons,  or  valleys  of  no  great  width.  Well  formed  terraces 
appear  at  many  points  along  Eel  river.  At  Humboldt  bay, 
where  this  river  comers  out  to  the  ocean,  the  higher  mountains 
stand  back  some  miles  from  the  coast,  and  there  intervenes  a  strip 
of  level  or  slightly  undulating  country.     A  part  of  this  land  about 


THE    PHYSTOGHAI'HY    OF   CAMFOUN'IA  29 

the  bay  is  of  delta  fonnation,  Init  tlie  iiujst  has  been  eroded  out  of 
a  soft  Pliocene  formation. 

Russian  river  exhibits  an  interesting  feature  in  its  lower 
€Ours(\  From  a  study  of  Sonoma  valley,  with  its  enclosinj^  moun- 
tains, one  would  naturally  expect  to  see  Russian  river,  which  drains 
it,  passing  southeasterly  into  San  Pal)lo  bay.  Th(?  river  does  not 
do  this,  however,  for  a  little  above  the  city  of  Santa  Rcjsa,  it  turns 
southwesterly  and  crosses  the  range  between  the  valley  and  the 
ocean  thru  a  winding  canon.  The  divide  separating  the  Sonoma 
valley  from  the  bay  is  very  low,  scarcely  noticeable.  It  is  probable 
that  the  stream  has  either  been  superimposed  upon  the  range 
which  it  crosses,  thru  the  removal  of  softer  materials  of  the  valley 
floor,  or  there  has  been  an  uplift  of  the  mountain. 

The  structural  and  topographic  features  of  the  coast  ranges 
south  of  San  Francisco  are  more  complicated  than  north.  The 
extension  of  the  Mount  Diablo  range  to  the  southeast,  forms  the 
real  crest,  or  backbone  of  the  Coast  Ranges.  This  divide  lies  very 
near  the  eastern  edge  of  these  mountains  the  whole  distance 
between  Mount  Diablo  and  their  southern  termination  in  the  San 
Emedio  mountains.  The  divide  varies  much  in  height.  East 
of  Livermore,  where  it  is  crossed  by  the  Southern  Pacific,  it  is  only 
eight  hundred  feet  high,  while  near  the  middle  of  the  range  a  height 
of  nearly  five  thousand  feet  is  shown  in  San  Carlos  peak. 

The  Mount  Hamilton  range  which  bounds  the  Santa  Cbira 
valley  upon  the  east  is  not  structurally  distinct  from  the  Mount 
Diablo  range.  The  Lick  observatory  stands  upon  Mount  Hamil- 
ton, the  culminating  i^eak,  at  nn  elevation  of  4.210  feet. 

The  Santa  Cruz  mountains  form  a  broad  elevated  block 
between  the  Santa  Clara  valley  and  the  ocean.  The  highest  peaks 
of  the  range  rise  to  8,500  feet  or  over.  Following  this  range  south- 
easterly we  find  it  gradually  decreasing  in  height  until  we  reach 
the  broad  and  low  depression  separating  it  from  the  Gavilan  range 
which  is  structurally  a  continuation  of  the  Santa  Cruz  range  to  the 
southeast.  During  the  Pleistocene  submergence,  there  was  here 
as  at  San  Francisco  a  broad  channel  permitting  the  entrnnce  of 
the  ocean  into  the  large  valleys  within  the  Coast  Ranges.  A  divide 
of  but  little  over  three  hundred  feet  separates  the  Santa  Clara  val- 
ley from  the  San  Benito  valley,  while  the  divide  between  the  San 
Benito  and  the  oc(^an,  discarding  the  Pajaro  canon,  has  about  tiie 
same  height.     The    San  Benito  drainage  may   at  one   tinu'   have 


30 


THE    PHYSIOGRAPHY    OF    CALIFORNIA 


p:ono  down  thru  the  Santa  Clara  valley  into  San  Francisco  bay. 
There  are  good  reasons  for  thinking  that  the  reverse  was  the 
case  at  one  time,  owing  to  the  presence  of  a  great  submarine  valley 
in  the  bay  of  Monterey  and  none  opposite  the  Golden  Gate.  At 
present,  however,  the  Pajaro  river,  draining  the  San  Benito  valley, 
has  ciit  a  narrow  canon  thru  tlic  low  pass  separating  the  Santa 
Cruz  range  from  the  Gavilaii  and  passes  directly  out  to  the  ocean 
at  Monterey  bay. 

The  Gavilan  range  as  a  distinct  mountain  block  has  a  length 
of  about  sixty  miles  when  it  blends  with  the  Mount  Diablo  range. 
At  its    southern  (^nd  ar(>   two  ]iromiii(^nt  elevations  known  as  the 


NKAK  THE  SUMMIT  OF   MOUNT  LOWB. 

Chalone  peak.  The  higher  one  is  an  ancient  volcano  of  Tertiary 
age.  The  hardened  tuffs  to  the  north  have  weathered  out  in 
pinnacled  forms  of  pictures(pie  appearance. 

The  union  of  the  Pajaro  and  Salinas  valleys  forms  th(^  exten- 
sive lowlands  about  the  bay  of  Monterey.  These  wen^  formed  in 
great  j^art  during  the  last  deep  submergence  of  the  coast.  The 
Salinas  river,  with  its  important  tril)utary,  the  Estrella,  occupies 
the  longest  and  most  direct  vaUey  of  the  Coast  Ranges.     Near  the 


THE    PHYSIO(iRAPHY    OF    CALIFORNIA  31 

bay  the  valley  is  shut  in  between  hi^di  mountains.  Toward  the 
southeast  the  valley  narrows  and  the  mountains  become  lower. 
In  the  middle  and  upper  portion  of  the  })a8in,  there  are  broad 
reaches  of  open  valley  and  low  hills.  On  account  of  the  semi-arid 
conditions  prevailint^  in  portions  of  tlu;  basin,  the  Salinas  river, 
except  durinti;  uncommonly  wet  seasons,  is  an  insip;niHc,iiit  one. 
During  the  sunnner  its  bed  is  dry  in  many  places. 

The  mountain  ranges  which  shut  in  the  valley  of  the  hnver 
Salinas  contrast  cpiite  strongly  with  each  other.  The  Gavilan  upon 
the  east,  tho  attaining  an  elevation  of  three  thousand  feet,  has  only 
moderately  steep  slopes  and  presents  the  general  appearance  of 
much  greater  age  than  the  Soledad  hills  uix)n  the  west.  The  lat- 
ter rise  also  to  about  three  thousand  feet  Imt  present  a  steep  and 
picturesque  scarp  tow^ard  the  valley.  The  Salinas  river  flows 
close  under  this  regular  mountain  wall,  a  fact  which  would  indi- 
cate a  recent  dropping  of  the  valley  floor  upon  that  side.  Remark- 
ably fine  examples  of  debris  fans  are  found  along  the  steep  slope 
of  the  mountains. 

The  Soledad  hills  form  but  th(>  eastern  ridge  of  a  much  higher 
and  more  important  mountain  block  known  as  the  Santa  Lucia 
range.  This  range  begins  in  the  pictui'csque  and  rugged  coast 
near  Monterey  and  extends  southeasterly  along  the  ocean  for  about 
one  hundred  miles.  It  then  passes  inland,  giving  place  i;pon  the 
shore  to  another  range.  The  Santa  Lucia  finally  l)lends  with  the 
San  Rafael  and  other  mountains  in  eastern  Santa  Barbara  county, 
and  these  in  turn  with  the  San  Emedio  mountains.  The  Snnta 
Lucia  is  the  most  rugged  and  i:)ictures(pie  mountain  range  in  the 
coast  region  of  California.  Its  crest  is  from  three  thousand  to  Ave 
thousand  feet  high,  and  lying  as  it  does  oidy  about  five  miles  from 
the  sea  shore,  the  ocean  slope  of  these  mountains  is  exceedingly 
rugged  and  picturescpie.  In  many  plac(>s  they  rise  with  steep  slopes 
from  precipitous  ocean  cliffs,  l^pon  the  eastern  slope  of  the  range, 
the  canons  which  unite  to  form  the  Arroyo  Seco  are  deep  anil  nar- 
row. The  region  is  one  of  sharp  ridges  and  canons  but  scantily 
clothed  with  timber.  The  highest  peak  of  the  range  is  San  Lucia, 
seven  thousand  feet  high. 

The  San  Luis  range  is  that  mountain  block  which  replaces  tiie 
Santa  Lucia  upon  the  coast  toward  the  south.  The  seaward  pro- 
longation of  this  range  forms  a  projei-ting  lu>adland  known  as 
Point  Buchon.     At  the  moutli  of  Morro  bav,  a  few  mili'S  north   of 


32 


THE    PHYSIOGRAPHY    OF    CALIFOEXIA 


this  point,  stands  a  .<2;roat  rock  rising;  bare  and  precipitous  from  the 
ocean  to  a  height  of  nearly  six  hundred  feet.  It  is  known  as 
Morro  rock  and  is  by  far  the  most  strikinsj;  single  feature  of  the 
coast  of  California.  It  is  formed  of  a  very  resisting  igneous 
intrusion.  This  rock  is  but  one  of  a  seri(»sof  similar  peaks  extend- 
ing itilaiid  ill  a  soiilhcastcrly  direction   ihru   the   San   Luis  valley. 


A  SCENE  I.\  THE  YOSEMITE  VALLEY. 

Several  of  tlieni  I'ise  from  tJie  opiMi  valley  to  a  height  of  twelve 
hundred  to  fourteen  hundred  feet  in  ragged  and  picturesque 
forms.  They  result  from  differential  erosion  in  rock  masses  of 
greatly  varying  hardness. 

A  nnnarkable  and  interesting  valley  lies  to  the  southeast  of 
the  extreme  head  of  the  Estrella.  a  tributary  of  the  Salinas.  It  is 
known  as  the  ('arriso  plain,  havinga  lengtli  of  al)oat  fifty  miles  and 
a  width  of  ten.  A  scarcely  noticeable  divide  separates  the  plain 
from  the  basin  of  th<>  Salinas.  As  it  is.  this  great  stretch  of  country 
shut  in  on  most  sides  ])v  low  mountains  has   no   outlet.     The  sink 


THE    rHYSIOGUAl'HY    OF    CALIFOKXIA  33 

at  its  centre  is  occupied  by  a  salt  marsh  of  considerable  extent. 
The  arid  conditions  prevailing  here  have  kept  the  valley  from 
being  flooded  and  bn^aking  the  slight  barrier  l)etween  it  and  the 
Salinas.  As  will  be  seen  later,  the  floor  of  this  plain  is  continuous 
with  an  old  peneplain  occupying  the  upper  Salinas  valley.  This 
is  remarkable  as  being  the  oidy  inclosed  basin  in  the  Coast  Ranges. 

The  Cuyamas,  or  as  it  is  known  in  its  lower  portion,  the 
Santa  Maria,  is  one  of  the  most  interesting  rivers  of  the  Coast 
Kanges.  It  rises  far  to  the  southeast  in  the  San  Emedio  moun- 
tains and  flowing  northwesterly  for  many  miles  bt^tween  the  Mount 
Diablo,  or  rather  the  southern  extension  of  that  range,  and  the  San 
Rafael  mountains  finally  turns  abruptly  southwesterly,  leaving  the 
broad  Cuyamas  valley,  and  canons  directly  across  the  Santa  Lucia 
range  to  the  ocean.  The  Cuyamas  valley  was  probably  formed  as 
a  consequence  of  fault  movements  which  left  it  without  an  outlet. 
A  lake  resulted,  and  in  the  overflow  of  the  lake  originated  the 
stream  which  cut  the  present  canon. 

The  extreme  southeastern  portion  of  the  Coast  Ranges  form 
a  rugged  and  complex  group  of  mountains  known  as  the  San 
Rafael  mountains.  They  are  largely  covered  with  dense  brush, 
altho  there  is  some  timber  where  the  conditions  are  favorable. 
The  canons  are  deep  and  show  but  little  or  no  bottom  land.  From 
this  region  the  Sisquoc  and  Santa  Ynez  rivers  flow  westerly,  the 
Ojai  and  Sespe  southerly,  Zaca  lake  is  a  small  but  well  known 
body  of  water  in  the  western  part  of  the  range.  It  occupies  the 
valley  of  a  small  stream  which  had  graded  its  valley  to  correspond 
with  the  conditions  existing  when  the  coast  was  depressed  about 
eight  hundred  feet. 

The  Santa  Ynez  is  a  regular  and  continuous  range  which 
borders  the  coast  from  Point  Arguello  easterly.  Upon  the  north 
is  the  l)road  valley  of  the  Santa  Ynez  river,  while  upon  the  south  a 
narrow  strip  of  land  separates  it  from  the  ocean.  This  strip  of 
land  is,  however,  fertile  and  highly  cultivated.  The  city  of  Santa 
Barbara  is  situated  upon  it. 

From  the  foregoing  description  it  may  be  judginl  that  the 
larger  valleys  of  the  Coast  Ranges  have  not  developed  contempo- 
raneously with  the  canons  in  the  mountains  which  enclose  tht>m. 
The  canons  correspond  in  their  stage  of  development  fairly  well  to 
those  in  the  Klamath  mountains  and  the  Sierra  Nevada,  but  the 
valleys  have  had  a  longin-  history.     It  is  a   compU'x   history   to  be 


34 


THE    PHYSIOGRAPHY    OF    CALIFORNIA 


sure,  hut   structural  conditions   rather  than    erosion    have  deter- 
mined in  most  cases  the  position  and  character  of  the  valleys. 

As  illustratinu;  how  structural  conditions  have  affected  the 
topoecraphy,  there  might  be  mentioned  a  line  of  narrow  valleys 
extending  from  the  northern  portion  of  the  Sierra  Madre  mountains 
across  the  San  Emedio,  and  northwest  thru  the  Coast  Ranges  toward 
San  Francisco.  These  valleys  have  been  eroded  as  a  result  of  earth- 
([uake  movements  in  recent  times.  In  fact  the  formation  of  fis- 
urcs  and  low  ridges  resulted  along  this  line  from  an  earthquake  not 


PASADENA   AND  THE  SIERRA   MADRE. 

more  than  forty  years  ago.  The  line  of  movement  or  fissure  zone 
is  in  places  half  a  mile  wide,  and  many  distinct  ridges  and  depres- 
sions can  be  counted.  Springs  issue  from  this  zone  of  broken  rock 
and  erosion  is  proportionately  rapid. 

As  has  already  been  stated  the  peneplain  which  was  devel- 
oped thru  Tertiary  time  upon  the  slopes  of  the  Sierra  Nevada 
mountains,  th(>  Klamath  mountains,  and  lirobably  also  in  southern 
California,  cannot  be  traced  continuously  thru  the  Coast  Ranges 
owing  to  the  strong  deformation  experienced  in  this  region  in  late 
Tertiary  tim(\  as  well  as  to  the  fact  that  during  long  intervals  in  the 


THE   PHYSIOGRAPHY   OF   CALIFORNIA  35 

Tertiary  the  central  and  southern  portions  of  the  Coast  Ran^a-s 
were  submerged  beneath  the  sea. 

The  fact  that  the  main  valleys  of  tlie  Coast  Ran<^es  exliibit  an 
apparently  advanced  phase  of  development,  and  that  the  main 
streams  are  generally  sul)S(^(inent,  does  not,  then,  indicate  that  this 
region  has  been  elevated  longer  than  the  Sierra  Nevadas. 

The  peneplain  of  the  Klamath  mountains  can  be  traced  con- 
tinuously southward  nearly  to  San  Francisco  bay,  descending  slowly 
from  a  height  of  three  thousand  to  four  thousand  feet  in  the 
former  region  to  about  1,500  feet  near  its  southern  limit.  The 
planation  was  not  complete  for  scattered  peaks  rise  above  this 
plain.  During  the  development  of  the  peneplain  the  most  of  the 
streams  had  adjusted  themselves  to  the  structural  conditicjus. 
With  the  uplift  they  retained  these  courses  so  that  we  have  now 
well  adjusted  streams  where  we  miglit  expect  consequent  ones. 

With  the  close  of  the  Pliocene,  folding  and  faulting  inaugu- 
rated new  conditions  thru  much  of  the  Coast  Range  area.  In  the 
northern  portion  the  old  i^lain  was  distorted  l)ut  not  broken. 
Many  of  the  flat-to^jped  crests  of  mountain  ranges  south  of  San 
Francisco  bay  probably  date  from  the  late  Tertiary.  One  of  the 
most  important  of  these  is  to  be  observed  upon  the  Santa  Lucia 
range.  In  the  middle  portion  of  the  range  there  is  an  area  fully 
ten  miles  across,  and  many  miles  long,  which,  altlio  now  deeply 
dissected,  yet  presents  an  almost  level  sky  line  at  an  elevation  of 
about  three  thousand  feet.  There  are  many  other  areas  of  simihir 
character  scattered  thru  the  central   and  southern  Coast   Ranges. 

Following  the  post-Tertiary  disturl)ances,  and  during  the 
interval  of  the  early  Pleistocene  submergence,  when  the  coast  was 
one  thousand  to  fifteen  hundred  feet  below  the  present  level,  con- 
ditions must  have  been  favorable  in  places  for  the  extension  of 
the  Tertiary  peneplain,  and  for  the  evolving  of  joartial  plains  of 
erosion  upon  the  newly  formed  mountains  as  in  th(^  case  of  the 
Berkeley  hills  where  there  are  strong  indications  of  peneplanation 
at  an  elevation  of  about  1,500  feet. 

As  the  coast  began  to  rise  from  the  Pleistocene  submergence 
it  remained  long  at  a  height  above  the  present  level  of  between 
750  to  1,000  feet.  Extensive  plains  corresponding  to  this  height 
were  formed  in  the  valley  of  the  SaKnas,  north  of  the  Santa  Ynez 
valley  and  in  other  places.  In  the  Salinas  valley,  owing  to  the  wide 
distribution   of   soft   rocks,    the    erosion    plain    was     particularly 


36  THE    PHYSIOGRAPHY    OF    CALIFORNIA 

extensive.  It  was  fully  150  miles  long  reaching  far  southeast  into 
the  Carisa  plains  and  across  the  crest  of  the  Coast  Ranges  into  the 
Great  valley. 

Since  the  elevation  of  the  coast  to  its  present  height,  broad 
valleys  have  been  eroded  in  this  plain  and  a  new  erosion  plain  is 
in  process  of  formation.  There  are  then  to  be  recognized  thru  the 
central  and  southern  Coast  Ranges :  ( 1 )  a  broken  and  deformed  plain 
of  Tertiary  age,  remaining  only  as  fragments  here  and  there;  (2) 
an  extensive  one  of  Pleistocene  age  but  slightly  deformed;  and  (3)  a 
recent  one  being  evolved  out  of  the  last.  In  the  northern  Coast 
Ranges,  the  Tertiary  plain,  tho  deeply  eroded  and  deformed,  is  con- 
tinuous. 

THE  KLAMATH  MOUNTAINS 

The  use  of  the  term  Klamath  mountains  has  been  limited  to 
that  portion  of  the  Coast  Ranges  lying  north  of  the  south  fork  of 
the  Trinity  river  and  extending  northwest  to  the  ocean,  and  into 
Oregon.  Theses  mountains  are  limited  upon  the  east  by  the  line  of 
contact  between  the  older  crystaline  rocks  and  the  lavas  of  the 
Cascade  range.  On  the  boundary  between  California  and  Oregon 
the  Klamath  mountains  join  the  Cascade  range  in  an  unbroken 
ridge,  but  l)oth  north  and  south  of  this  point  broad  valleys  sepa- 
rate the  two  mountain  ranges.  In  California  the  eastern  border  of 
the  Kin  math  mountains  extends  south  along  the  western  edge  of 
Shasta  valley,  then  easterly  around  the  southern  base  of  Mount 
Shasta,  and  then  bending  south,  follows  down  Pitt  river  to  the 
Sacramento.  Along  much  of  this  line  the  contrast  in  topography 
between  the  volcanic  plains  and  the  steep  slopes  of  the  Klamath 
mountains,  is  very  marked. 

Different  portions  of  the  Klamath  mountains  are  known  under 
different  names.  The  Siskiyou  range  forms  a  group  partly  in  Cali- 
fornia and  partly  in  Oregon.  The  Scott  and  Salmon  mountains 
lie  to  the  south  and  include  the  highest  peaks  of  the  whole  group, 
many  rising  from  seven  thousand  to  nearly  ten  thousand  feet.  The 
geological  structure  of  the  region  is  not  as  regular  as  in  the  Coast 
Ranges  to  the  south,  and  as  a  consequence  the  mountains  and  val- 
leys have  no  definite  arrangement.  The  streams  flow  in  deep,  and 
generally  narrow  canons,  except  in  a  few  cases  where  basins  inclos- 
ing softer  beds  than  those  forming  the  main  body  of  the  mountains 
have  given  rise  to  valleys  of  considerable  size.  Among  these  are 
Scott's  valley.    Hay  Fork  valley,  and  the  valley  about  Weaverville. 


THE    PHYSIOGRAPHY   OF    C'ALIFOKNIA 


37 


Amoiii?  the  larger  streams  are  the  Khimath,  Trinity,  ;im(1  Sac- 
ramento rivers.  The  Klamath  river  rises  in  the  Klamath  lake 
basin  east  of  the  Cascade  range  in  Oregon.  It  flows  southwesterly 
into  California,  and,  after  crossing  the  depressed  portion  of  the  Cas- 
cade range,  pursues  a  tortuous  course  in  a  deep  cafKJii  across  the 
Klamath  mountains  to  tlie  ocean.  The  mountains  trav('rs<'d  rise 
to  a  height  of  six  thousand  or  seven  thousand  feet,  and  th(!  ([ues- 
tion  naturally  arises  why  the  river  should  have  cut  across  these 
mountains  rather  than  have;  turned  southerly  thru  Shasta  valley 
where  a  low  divide  of  only  'AAOO  feet  elevation  above  the  sea  sep- 
arates it  from  the  basin  of  the  Sacranum'to  river.  In  this  case  the 
most  reasonable  explanation  seems  to  be  that  of  a  gradual  rise  of 


AVALON,  SANTA  CATALTNA  ISLAND.— A  harbor  made  by  the  partial    floodiii>;   ot 
a  valley  of  erosion.     Result  of  last  subsidence  of  the  coast. 

the  Klamath  mountiau   region  after  tlu^   river  had    actiuired    its 
present  course. 

The  source  of  the  Sacramento  river  is  in  large  springs  issuing 
from  the  lava  at  the  southwest  base  of  Mount  Shasta.  The  stream 
iSows  southerly  and,  after  leaving  the  lava,  crosses  a  spur  of  the 
Klamath  mountains  before  reaching  the  Sacramento  valley.  Its 
course  for  many  miles  is  thru  a  picturesque  canon      The  canon 


J70 


38  THE    PHYSIOGRAPHY    OF    CALIFORNIA 

antedates  the  latest  of  the  lava  streams  from  Shasta,  for  one  of 
them  flowed  down  thru  it  for  fifty  miles.  The  river  has  cut  thru  the 
lava  in  most  places  and  is  now  deepening  its  channel  again. 
Among  the  picturesque  features  of  the  upper  Sacramento  canon 
are  the  Castle  Crags,  bare  and  castle-like  pinnacles  of  granite. 

The  Trinity  river  drains  the  southern  portion  of  the  Klamath 
mountains.  The  basin  of  this  river  is  separated  from  the  Sacra- 
mento valley  by  Bully  Chooj)  mountains,  while  upon  the  north 
are  the  Salmon  and  Scott  mountains. 

The  higer  portions  of  the  Klamath  mountains,  particularly 
the  Salmon  range,  were  glaciated  during  the  Glacial  period.  The 
glaciers  were  more  local  than  those  in  the  Sierra  Nevada  moun- 
tains and  did  not  descend  below  five  thousand  feet.  The  higher 
mountain  valleys  contain  numerous  little  lakes,  which  with  the 
moraines  and  polished  rock  surfaces  are  characteristic  of  glaciated 
areas. 

Viewing  the  Klamath  mountains  as  a  whole,  we  find  that  they 
have  many  physiographic  characters  in  common  with  the  Sierra 
Nevada  mountains.  There  is  the  same  absence  of  isolated  peaks 
rising  much  above  the  elevated  ridges,  and  the  same  deep  canons 
carved  out  by  erosion.  Geologically  they  also  have  much  in  com- 
mon. 

THE  SIERRA  MADRE  AND  PENINSULA    RANGES 

Under  this  head  will  be  included  all  that  part  of  California 
lying  south  of  the  San  Emedio  mountains  and  west  of  the  Great 
Basin  area.  The  broad  and  high  range  of  mountains  extending 
south  of  east  from  the  San  Emedio  region,  forms  the  watershed 
between  the  fertile  valleys  of  southern  California  and  the  Mojave 
desert.  This  mountain  block  is  known  at  various  points  under 
different  names.  The  designation  Francisquita  mountains  is  given 
to  that  portion  lying  south  of  Antelope  valley  (western  arm  of  the 
Mojave  desert)  and  west  of  Soledad  pass.  East  of  this  pass  the 
range  broadens  and  becomes  much  higher,  reaching  an  elevation  of 
nine  thousand  feet  in  San  Antonio  peak.  This  portion  is  known 
as  the  San  Gabriel  range. 

At  Cajon  pass  the  range  is  again  depressed  sufficiently  to  per- 
mit of  its  being  crossed  by  a  railroad.  Beyond  the  pass  to  the 
east  rises  the  still  more  lofty  and  rugged  San  Bt^-nardino  range 
culininating  in  (Trayl)ack,  over  eleven  thousand  feet  high.     To  the 


THE    PHYSIOGRAPHY   OF   CALIFOUXJA  ;{<) 

east  the  raiiije  now  becomes  lower  and  forms  the  low  divide 
between  the  Mojave  and  Colorado  deserts. 

The  Sierra  Madre  range,  as  a  whole,  was  elevated  near  the 
close  of  the  Tertiary  period,  pro])ably  thru  the  combined  iiitluciicp 
of  folding  and  faulting.  The  sontheru  front  of  the  range  is  par- 
ticularly bold  and  imposing  rising  as  it  does  from  extensive  valleys 
and  waste  slopes  elevated  less  than  one  thousand  feet  a])ove  the 
sea.  The  mountains  are  deeply  cut  by  sharj)  \'-sliaped  canons  in 
which  are  insignificant  streams  during  the  dry  season.  After 
heavy  storms  each  carries  a  nniddy  torrent,  which,  spreading  out 
at  the  mouth  of  its  canon,  contributes  its  load  to  the  building  up 
of  the  waste  slope. 

But  one  stream  of  any  consequence,  the  Mojave  river,  drains 
the  northern  side  of  the  San  B(>rnardino  range,  and  it  is  soon  lost 
in  the  sands  of  the  desert.  Upon  the  southern  side  the  San 
Gabriel  and  Santa  Ana  rivers  are  the  most  important,  l)ut  even 
these  carry  but  little  surface  water  to  the  ocean.  The  most  of  it  is 
used  in  irrigation. 

The  Santa  Clara  river  drains  the  northern  portion  of  the  area 
under  discussion.  Its  tributaries  head  in  the  San  Emedio,  Fran- 
cisquita,  and  San  Gabriel  mountains.  In  the  middle  and  upper 
portions  of  this  basin  the  rainfall  is  light,  and  except  after  periods 
of  heavy  rain  but  little  water  flows  upon  the  surface  of  the  river 
bed.  The  valley  of  the  Santa  Clara  expands  to  a  width  of  twelve 
or  more  miles  near  the  ocean,  and  for  fifty  mili^s  l)ack  from  the 
coast  is  highly  cultivated.  Mounts  Pinos,  Alamo,  and  Frazier  upon 
the  northern  edge  of  this  basin  are  the  loftiest  peaks  of  th(^  San 
Emedio  range.  The  two  latter  peaks  in  particular  have  nearly  fiat 
summits  of  considerable  extent  which  appear  to  be  remnants  of  an 
ancient  peneplain.  The  Tertiary  and  Pleistocene  deposits  high  up 
on  the  flanks  of  these  mountains  testify  to  very  marked  elevation 
in  recent  geological  times. 

The  valley  of  the  Santa  Clara  rivt^r  seems  to  have  originated 
in  a  structural  depression  formed  thru  faulting.  The  San  Fer- 
nando range  bordering  this  vall(\v  upon  the  south  and  eight(H>n 
hundred  to  three  thousand  feet  high  givi^s  evidence  in  its  1)()1(1 
scarp  facing  the  valley,  and  gentle  slope  to  the  south,  of  l)eing  a 
raised  and  tilted  block.  The  valley  of  the  Santa  Clara  river  lias 
like  most  of  the  other  large  streams  had  its  lH>d  graded  ui)  in 
adjustment  to  the  present  conditions. 


40 


THE    PHYSKXIEAPHY    OF    CALIFORNIA 


Extending  east  and  west  along  the  north  side  of  Santa  Monica 
bay,  and  reaching  eastward  to  Los  Angeles,  is  another  mountain 
ridge  known  as  the  Santa  Monica  range.  Its  highest  peaks  reach 
an  elevation  of  nearly  three  thousand  feet.  The  range  is  formed 
largely  of  volcanic  rocks.  Structurally  it  appears  to  be  continuous- 
with  the  islands  to  the  west  lying  off  Santa  Barbara  channel. 

An  irregular  line  of  low  mountains  stretches  along  near  the- 
southern  base  of  the  San  Gabriel  range  and  is  separated  from  it  by 
a  waste  filled  valley.  In  the  eastern  end  of  the  San  Fernandez 
valley  this  elevation  is  known  as  the  Verdugo  mountains.  Farther 
east  are  the  San  Rafael  hills.  Between  Los  Angeles  and  Pasadena 
these  hills  are  much  eroded,  but  beyond  the  San  Gabriel  river  they 


MILL  VALLEY  AND  MT.    TAMALPAIS. 

rise  again  to  form  the  Puente  hills.  Tracing  them  farther  still, 
they  are  found  to  increase  in  height,  forming  the  steep  and  high 
Santa  Ana  range  whose  eastern  front  is  a  great  fault  scarp  of 
recent  geological  origin.  The  highest  peak  of  the  range  has  an 
elevation  of  5,600  feet. 

Between  the  San  Gabriel  river  and  San  Fernando  the  streams- 
issuing  from  the  San  Gabriel  range  have  cut  across  this  line  of  hills, 
and  mountains,  and  in  many  places  have  nearly  obliterated  them. 
The  waste  slopes  sweep  across  them  in  even  grade. 

Th(?  plain  stretching  from  Los  Angeles  south  and  west   to  the 


THE    PHYSIOGRAPHY   OF    CALIFORNIA  41 

coast  formed  the  floor  of  a  broad  bay  during  the  last  extensive^  sub- 
mergence of  this  region.  It  has  been  l)ut  slightly  moditicd  by 
erosion. 

The  Santa  Ana  is  the  largest  stream  of  southern  California. 
Rising  in  the  San  Bernardino  range  it  flows  westward  past  San 
Bernardino  and  Riverside  thru  a  region  of  low  relief,  and  then 
canons  thru  the  northern  end  of  the  Santa  Ana  range.  It  emerges 
from  the  caiion  upon  a  broad  flood  plain  which  extends  to  the  ocean. 
The  river  was  probably  either  superimposed  upon  the  Santa  Ana 
range  because  of  an  original  dej)Osit  of  soft  sediments  filling  the 
basin  thru  its  middle  course,  or  it  cut  the  canon  as  the  range  was 
slowly  elevated  across  its  course. 

The  old  topography  in  the  region  about  Riverside  is  most 
interesting.  The  graded  condition  of  the  streams,  the  low  hills  of 
granite  and  ancient  crystalline  schists  afford  us  a  picture  of  what 
nearly  the  whole  of  southern  California  might  have  been  if  it  were 
not  for  the  faulting  which  gave  rise  to  the  rugged  ranges  of  the 
region.  If  it  were  not  for  these  high  mountains  arid  conditions 
would  prevail  and  there  would  be  another  Mojave  desert. 

This  area  of  ancient  topographic  forms  stretches  south  from 
Riverside  for  many  miles  and  also  west  to  the  Puente  hills.  It 
presents  the  most  striking  contrast  to  the  bold  scarps  of  the  Santa 
Ana,  San  Bernardino,  and  San  Jacinto  ranges. 

South  of  the  San  Bernardino  range,  and  on  the  south  side  of 
the  low  pass  leading  east  to  the  Colorado  desert,  rises  the  rugged 
peak  of  San  Jacinto  to  a  height  of  about  eleven  thousand  tVet. 
twin  l>rother  to  Mount  San  Bernardino. 

Mount  San  Jacinto  may  be  termed  the  northern  end  of  the 
Peninsula  range,  that  continuous  chain  of  mountains  stretching 
from  this  point  south  for  nearly  one  thousand  miles  thru  the  penin- 
sula of  lower  California.  This  range  rises  as  a  general  thing 
very  abrul)tly  from  the  desert  and  gulf  at  its  eastern  base,  and  in 
position  and  structure  might  be  considered  a  worthy  continuation 
of  the  Sierra  Nevada  mountains.  The  lower  portion  of  the  scarp 
of  the  range  near  the  Mexican  line  is  particularly  bold.  Here 
recent  faulting  has  raised  the  niDiintains  abDut  one  thousand 
feet.  Upon  the  slope  of  Carrizo  mountain  mollusc  borings  still 
remain  upon  the  surface^  of  the  limestone  at  an  elevation  of  t\v."lv,> 

hundred  feet. 

The  western  portion  of   Mount   San   Jacinto,   overlooking^   tlir 


42  Tin:  iMivsiodiiAPHY  of  caltforxia 

hroad  reaches  of  llie  valley  of  the  same  name,  is  a  l)()l(l  fault  scarp. 
San  Jacinto  river  Ho\vin>j,-  for  some  distance  at  the  base  of  this 
scarp  turns  abruptly  southwest,  aud  crossinsi;  the  re,«;-ion  of  old 
topoj^raphy  already  describeil.  empties  in  seasons  of  exceptionally 
w.'t  weather  into  Lake  Elsinore,  th(^  lari;-(^st  lake  of  southern  Cali- 
fornia. This  lake  lii's  at  tlu^  (^astern  base  of  the  southern  con- 
tinuation of  the  Santa  Ana  fault  scarp,  and  occasionally  overflows 
northwesterly  down  the  Temescal  vall(\v  to  the  Santa  Ana  river. 

FoUowiui?  the  fault  scarp  from  Elsinore  for  thirty  miles  in  a 
southeasterly  dircK-tion  we  come  to  T(unecula  creek,  a  stream  of 
consid(>ral)le  size  risinti;  to  the  south  of  San  Jacinto.  This  stream 
instead  of  llowinu;  northw(>st  alono-  the  base  of  the  scarp  as  we 
should  naturally  expect  it  to  do,  has  instead  cut  a  canon  directly 
across  tlit»  scarp  and  pursues  a  fairly  direct  course  to  the  ocean. 
Here  as  in  many  other  cases  there  are  two  hypotheses  to  choose 
from  to  account  for  the  course  of  the  stream.  Either  the  moun- 
tain scarp  has  been  slowly  raised  across  its  course  or  the  valley 
in  the  depressed  ])lock  to  the  east  of  the  fault  was  filled  with  pleis- 
tocene deposits  to  a  level  with  the  rim  of  the  scarp  at  the  time  the 
draina.u-e  was  established.  Which  explanation  is  the  correct  one 
has  not  yet  been  determined. 

The  canon  wliicli  tlie  stream  has  cut  is  narroAv  and  (piite  pic- 
turesque. Standing-  at  the  top  of  the  present  steep  walled  canon 
we  appear  to  be  in  the  centre  of  a  l)road  valley  of  older  topographic 
forms,  a  valley  eroded  and  fairly  matured  before  the  last  uplift. 

South  of  Temecula  the  fault  scarp  disappears  altho  Smiths 
mountain  which  appears  to  be  an  uplifted  block  may  be  related  to 
the  same  line  of  disturbance.  Toward  the  southern  boundary  of 
the  state  the  Peninsula  range  becomes  more  simple.  Back  of  San 
Diego  the  crest  of  the  rang(^  is  nearly  as  far  from  the  fault  line  at 
its  eastern  base  as  from  the  western.  The  features  of  an  ancient 
baselevel  are  particularly  noticeable  upon  the  crests  of  the  moun- 
tains and  ridges.  The  sunnnit  of  Smiths  mountain  as  well  as  that 
of  the  Laguna  mountains  are  fine  examples  of  flat  topped.  Viewed 
from  a  point  east  of  Falllu'ook  the  western  slope  of  the  mountains 
forms  a  nearly  even  sky  line  gently  (lii)i)ing  towards  the  coast. 
The  present  canons  have  been  eroded  in  this  ancient  plain,  and  in 
many  cases  they  have  wid(Mied  to  extensivt^  valleys.  The  main 
streams  are  comi)letely  graded,  flowing  over  a  sand  floor.  Their 
beds  are  dry  during  a  great  part  of  the  year  but  water  can  be 
oblaineil  in  al)iiii(laii<-c  bv  sinking  tliru  the  sand. 


THE  physi()(;haphy  of  camfornia  4;i 

Th(M^xt('tisiv(uiK'sa  oxtoiidiii.o- from  San  Dic^^o  to  ofcan  side 
is  an  old  sea  floor.  Excei^t  for  the  steep  walled  canons  cnit  across 
it  tli(^  surfac(>  has  been  but  slightly  modified  since  the  uplift.  One 
can  trac(^  in  places  th(^  successive  lines  of  sand  dunes  formeil  as  tin- 
coast  rose.  San  Diego  bay  has  probably  b('en  formed  thru  the 
drowning  of  a  river  vaUey  in  conruK-tion  with  the  action  of  ocean 
waves  and   currents. 

COAST    FEATURES 

The  fact  has  already  been  mentioned  that  along  the  whole 
length  of  the  California  coast  the  topography  resulting  from  sub- 
aerial  erosion  has  been  modified  by  wave  action  and  sedimentation 
incident  to  depressions  of  the  coastal  area.  The  lower  portions  of 
the  stream  valleys  once  excavated  deeper  than  they  now  appear 
were  partly  filled  with  sediments  when  the  ocean  level  was  1000  to 
1500  feet  higher..  At  the  next  i^eriod  of  elevation  stream  erosion 
was  again  active.  Now  the  valleys  are  again  being  silted  up  to  sea 
level  as  a  consequence  of  submergence. 

Nearly  every  stream  along  the  whole  length  of  the  coast  has 
either  a  tidal  lagoon  at  its  mouth,  the  tide  entering  from  a  few 
hundred  yards  to  a  number  of  miles,  or  an  extensive  alluvial  plain. 
Those  streams  like  the  Klamath  river,  containing  a  large  volume 
of  water  the  year  around,  maintain  an  open  channel  to  the  st'a,  the 
tide  flowing  in  and  out.  The  entrance  to  San  Francisco  bay  is 
preserved  not  so  much  thru  the  volume  of  the  river  which  finds  its 
outlet  here  as  thru  the  vast  amount  of  tidal  water  pouring  thru  the 
Golden  Gate. 

Those  streams  like  the  Salinas  which  flow  a  considerable 
amount  of  water  for  only  a  portion  of  the  year,  and  whose  channels 
are  deeply  filled  with  detrital  material  do  not  show  the  efl'ects  of 
subsidence  as  distinctly  because  of  the  fllling  in  of  their  estiiaries. 
Along  the  southern  coast  there  are  many  streams  of  this  char- 
acter. There  are  other  sm;ill  streams  flowing  only  during  wet 
weather  and  which  carry  but  a  small  amount  of  the  detrital  nuiter- 
ial.  During  the  sunnner  the  waves  and  ocean  currents  block  the 
outlets  of  these  and  the  enclosed  lagoons  on  drying  leave  a  surfac*' 
whitened  with  more  or  less  salt.  These  conditions  are  beautifullv 
shown  along  the  coast  of  San  Diego  county  where  the  can'ms  of 
many  sni:dl  streams  have  been  flooded  by  sul)sidence. 

NuuKn-ous   wave-cut    ternices    of    varying     width    arc     i<>     be 


44  THE    PHYSTOGEAPHY    OF    CALIFORNIA 

observed  at  favorable  points  alonp;  the  whole  coast  of  California. 
These  ranu-e  from  ten  feet  to  fiiiteen  hundred  feet  in  elevation. 

The  p;reat  mesa  north  of  San  Dleijo  is  a  wave  cut  plain.  Its 
iip^HT  limit  has  an  elevation  of  about  (ML!;ht  hundred  feet. 

San  Pedro  hill,  forminsi;  a  prominent  feature  of  the  coast 
o])i)osit(>  Los  Ant2;eles,  is  fijiely  terraced  up  to  an  elevation  of 
twelve  liuiidrcd  feet.  San  Clemente  island,  which,  like  the  other 
islands.  stH'nis  to  have  movcnl  in  the  main  with  tlu^  mainland,  is 
terrac-ed  up  to  nearly  fifteen  hundred  feet. 

At  Point  Sal.  in  northwestern  Santa  Barbara  county,  there  is 
a  broad  terrace  at  one  thousand  feet.  Upon  the  seaward  slopes  of 
San  Luis  rantj^c^  there  are  many  terraces,  some  of  them  remarkably 
perfect,  they  rariy-e  in  height  from  ten  to  750  feet.  Upon  the 
slopc^s  of  the  Santa  Lucia  range  they  appear  at  heights  of  750  to 
one  thousand  ivvt.  Very  fine  terraces  also  appear  along  the  slopes 
of  the  Santa  Cruz  range.  North  of  the  mouth  of  Russian  river 
they  are  n^cognizable  as  high  as  fifteen  hundred  feet.  Th(^  upper 
one  forms  a  bench  against  the  old  penei^lain  so  distinctly  shown 
in  that  region. 

As  the  land  rose  iDcrmitting  the  formation  of  these  terraces, 
there  was  a  prolonged  stop  at  an  elevation  varying  from  750  to 
one  thousand  feet;  the  difference  between  these  figures  possibly 
indicating  the  amount  of  differential  movement  since.  The  breadth 
of  this  terrace  and  its  correspondence  in  height  to  the  l)road  pene- 
plain of  Pleistocene  age  which  is  very  prominent  tliru  portions  of 
the  Coast  Ranges  marks  this  as  an  important  stage. 

As  the  coast  rose  the  rivers  also  formed  terraces.  Below 
Bradley  upon  the  Salinas  river  six  terraces  can  be  seen. 

Along  nearly  the  whole  length  of  the  state  except  where  the 
mountains  rise  directly  from  the  ocean  cliffs  there  is  a  coastal 
l)lain.  This  varies  in  width  from  a  fourth  of  a  mile  to  several 
miles,  and  in  height  from  sixty  to  two  hundred  feet.  Along  por- 
tions of  the  Mendocino  coast  where  this  plain  is  broad  and  fur- 
nishes a  large  part  of  the  best  land  in  the  county,  much  of  it 
attains  a  height  of  four  hundred  feet. 

The  coast  of  California  is  bordered  by  a  submarine  plateau 
s]iar[)ly  marked  off  from  the  deep  waters  of  the  ojjen  Pacific. 
This  plateau  is  a  part  of  the  continental  mass  and  has  at  various 
times  in  its  history  been  wholly  or  in  part  raised  above  the  water. 
The  present  islands  rise  from  the  surface  of  this  plateau,  and  rep- 


THE    PHYSIOGRAPHY    OF    (Ar.IFoKNlA  45 

resent  peaks  of  iiioiiiitaiii  ranges  structurally  related  to  those  upon 
the  adjoining  niainhuid. 

The  sulnnarine  i^hitean  is  ({uite  narrow  along  the  coast  of 
northern  California.  From  point  Arena  S(juth\vard  it  slowly  widt-ns 
sweeping  just  outside  of  the  Farrallon  islands,  twenty  miles  otf 
the  Golden  Gate.  The  surface  of  the  plateau  generally  slopes  very 
gradually  out  to  the  one  hundred  fathom  curve  when  it  takes  on 
a  much  steeper  descent  to  the  deeper  portions  of  the  plateau  or  to 
the  abyssal  depths  of  the  Pacitic. 

The  plateau  narrows  opposite  Monten^y  l)ay,  and  along  the 
high  Santa  Lucia  range  the  one  hundred  fathom  curve  is  only 
4.()  nules  from  shore.  Farther  south  it  widens,  sweeping  out 
side  of  the  channel  islands,  and  finally  attaining  a  width  of 
150  miles.  The  surface  of  the  broad  portion  of  the  plateau  is  far 
from  being  uniform.  Some  of  the  islands  rise  over  two  thousand 
feet  above  the  sea  level,  and  in  places  the  dejith  of  the  water  at 
their  bases  is  two  thousand  to  three  thousand  feet.  An  elevation 
of  less  than  one  thousand  feet  would  connect  the  Channel  islands 
(those  lying  otf  Santa  Barbara)  with  the  mainland.  Such  an  ele- 
vation existed  during  the  early  Pleistocene,  for  remains  of  the 
mastodon  and  other  mammals  are  found  upon  one  of  them.  The 
water  about  San  Clemente  and  Santa  Catalina  is  much  deeper. 

Crossing  this  marginal  plateau  at  various  points  are  sul^ma- 
rine  valleys  which  from  their  position  and  general  character  are 
believed  to  have  been  formed  by  subtBrial  erosion.  Many  of  the 
most  prominent  valleys  lie  opposite  the  mouths  of  the  present  lan<l 
valleys,  some  are  not  thus  situated.  The  greatest  of  the  subma- 
rine valleys  is  that  occupying  the  bay  of  Monterey.  It  extends 
westerly  from  a  point  ntnir  the  mouth  of  the  Pajaro  and  Salinas 
rivers  and  down  across  the  plateau  to  the  abyssal  depths  of  the 
Pacific.  It  reaches  so  close  to  the  shore  as  to  have  influenced  the 
location  of  a  wharf.  It  has  been  thought  that  because  of  the 
absence  of  any  submarine  valley  opposite  the  Golden  Gate  the 
drainage  of  the  Great  valley  once  entered  the  ocean  thru  the  val- 
ley in  Monterey  bay. 

Many  important  and  interesting  facts  connected  with  the 
physiographic  history  of  California  yet  remain  to  be  studied. 
Enough  has  been  said  however  to  give  some  conception  of  the 
varied  features  of  the  state,  and  to  show  the  richness  of  tlu>  geo- 
graphic material  at  hand  for  our  schools. 


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